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This Chile Relleno Casserole layers roasted poblanos and melty cheese under a lightly seasoned egg mixture, then bakes until golden and set. You get all the flavor of chiles rellenos with none of the battering and frying. It slices clean and works just as well for brunch as it does for dinner.
More cheesy Mexican bakes: Green Chicken Enchilada Casserole | Mexican Chicken Casserole | Mexican Lasagna
Before You Get Started
Two things decide how this casserole turns out: how you handle the peppers, and what cheese you use. Get those right and the rest is layering.
- Char the peppers until they’re truly blackened. Then steam them covered for a full 10 minutes. Under-charred skins won’t slip off cleanly.
- Blot every pepper dry. Wet peppers are the number one reason a chile relleno casserole turns out watery.
- Use Monterey Jack as your base cheese. It melts smooth and creamy where cheddar can turn greasy and separate.
RECIPE WALK-THROUGH
How to Make Chile Relleno Casserole
See the recipe card below for full, detailed instructions
The peppers are the only part of this that takes real effort. Once they’re charred and peeled, everything after is layering, pouring, and waiting.
Step 1: Char and Peel the Poblanos
Lay 8 poblanos on a sheet pan and slide them under the broiler on high. Rotate them every few minutes until the skins are blackened and blistered all over, not just on top. This is where the smoky flavor comes from, so let them get darker than feels comfortable.
Move them straight into a bowl, cover it tightly with plastic wrap, and walk away for 10 minutes. The trapped steam is what loosens the skins, and skipping it is why peppers get frustrating to peel.
Peel with a paper towel rather than your fingers. It grabs the skin and blots away moisture at the same time.
Cut each pepper lengthwise into 2 strips, pull out the stem and seeds, and give the strips one more pass with a dry paper towel.
- If the skins are fighting you, the peppers either weren’t charred enough or didn’t steam long enough. Pop them back under the broiler for a few minutes instead of scraping. Scraping tears the flesh and leaves bitter bits of skin behind.
- No broiler? Roast the peppers on a sheet pan at 425°F for 15 to 20 minutes, until blistered. You can also char them one at a time directly over an open gas burner, turning frequently with tongs. Either way, steam and peel them the same.
- Short on time? Four 7-ounce cans of whole green chiles will stand in for the fresh poblanos. Drain them well and blot them dry with paper towels first. You’ll lose some of the smoky depth that charring builds, but you’ll save about half an hour.
- Once you’ve got the hang of charring poblanos, my Chicken Stuffed Poblano Peppers put the same skill to work.
Step 2: Cook the Onion and Garlic
Warm a teaspoon of neutral oil in a medium skillet over medium heat. Add ½ cup finely diced yellow onion and cook 3 to 4 minutes, until softened and translucent. Stir in 2 cloves of pressed garlic, give it 30 seconds, and pull the pan off the heat.
Don’t skip this and layer the onion in raw. It won’t fully soften in the oven, and you’ll get crunch where you want sweetness.
Step 3: Layer the Casserole
Preheat the oven to 350°F and grease a 9×13-inch baking dish.
Lay half the poblano strips flat across the bottom, overlapping slightly so there aren’t bare spots. Scatter half the cheese over them, then half the onion mixture. Repeat with the remaining peppers, cheese, and onions.
Keep the layers even. It’s the difference between every slice tasting the same and a few sad corner pieces.
- Save some cheese for the end: Hold back a small handful of the Monterey Jack and scatter it over the top layer. It browns into those golden spots that make the finished casserole look like it came out of a restaurant kitchen.
- Want to make it heartier? A cup of cooked chorizo or shredded chicken goes in with the onion layer. Add about 5 minutes to the bake time.
Step 4: Mix and Pour the Egg Layer
In a large bowl, whisk 6 eggs, ½ cup whole milk, ⅓ cup flour, ½ teaspoon baking powder, the cumin, salt, and pepper until completely smooth. Take an extra few seconds to whisk out any lumps of flour, because they won’t cook out in the oven.
Pour it evenly over the whole casserole rather than dumping it in one spot, so it settles down through the layers.
The flour and baking powder are doing real work here. They give the egg layer a little lift and structure, so it bakes up closer to a soufflé than a flat frittata.
Step 5: Bake and Rest
Bake for 35 to 40 minutes. You’ll know it’s done when the center is set and no longer jiggles, the top is golden brown, and the edges have started to pull away from the sides of the dish.
Let it rest 10 minutes before you cut into it. The egg keeps setting as it cools, and that rest is the difference between a clean square and a puddle on the plate.
Serve it with sour cream, lime wedges, and chopped cilantro. A spoonful of Homemade Salsa on top is all it really needs.
Building a bigger Mexican spread? My Taco Night Ideas collection covers the mains, sides, and toppings to fill the table.
What to Serve Alongside
Rice and beans are the natural move here. A scoop of each alongside turns a square of casserole into a full plate, and both can cook while the casserole bakes.
A few options from the site: Mexican Rice | Homemade Refried Beans | Mexican Black Beans
The casserole is rich, so something bright helps balance it. A simple garden salad with a squeeze of lime, or a few slices of avocado, is plenty. Warm tortillas are worth putting on the table too.
If you’re serving it for brunch instead, it holds its own next to fresh fruit and a pot of coffee. No sides required.
Storage Tips
Storage, Freezing, and Make Ahead
Store leftovers covered in the fridge for up to 3 days. This one is genuinely best the day it’s made, since the peppers soften as they sit.
To reheat a full pan, put it in a 350°F oven uncovered for about 20 minutes, until warmed through. Leaving it uncovered is what keeps the top from going soggy. For a single portion, the microwave does the job in 30 seconds to a minute.
Freezing isn’t recommended: Poblanos lose their texture in the freezer and thaw out limp and watery, which undoes all the work you put into charring them.
Make-ahead: Don’t assemble the casserole in advance. The egg mixture separates as it sits and the peppers start releasing liquid into it. What you can do ahead is the prep. Char, peel, and slice the peppers up to 2 days early and keep them in an airtight container in the fridge, and cook the onion and garlic at the same time. Come dinnertime, you’re about 15 minutes from the oven.
Frequently Asked Questions
Why is my chile relleno casserole watery?
Almost always one of three things. The peppers weren’t blotted dry before layering, canned chiles weren’t drained well enough, or it got sliced before it had time to rest. A little moisture is normal. A puddle means one of those three happened.
My peppers were hard to peel. What went wrong?
The skins only slip off easily when the peppers are charred thoroughly and steamed long enough. Every side needs to be blistered, not just the side facing the broiler, and they need the full 10 minutes covered. If they’re still fighting you, back under the broiler is the fix.
Can I use a different pepper instead of poblano?
Anaheim and Hatch chiles are the closest swaps in size and heat level. Canned whole green chiles work when you want the shortcut. Jalapeños are a different story: much hotter and too small to layer the same way, so they’re better chopped and mixed in than used as the base.
Can I use mozzarella or queso fresco?
Neither one on its own. Fresh mozzarella holds too much water and will thin out the egg layer, and queso fresco doesn’t really melt. Stick with Monterey Jack as the base, then add pepper jack if you want heat or mild cheddar if you want something more familiar.
More Mexican Comfort Food
- Breakfast Enchilada Casserole
- Easy Tamale Pie
- Southwest Chicken Bake
- Green Chile & Sour Cream Chicken Enchiladas
- Chicken Poblano Soup
Chile Relleno Casserole
Ingredients
- 1 tsp neutral oil such as canola
- ½ cup yellow onion finely diced
- 2 cloves garlic pressed or minced
- 8 fresh poblano peppers
- 6 large eggs
- ½ cup whole milk
- ⅓ cup all purpose flour scooped
- ½ teaspoon baking powder
- 2 cups shredded Monterey Jack cheese
- 1 cup shredded pepper jack cheese or cheddar for less heat
- ½ teaspoon ground cumin
- ¾ teaspoon kosher salt
- ¼ teaspoon freshly cracked black pepper
Instructions
- Place the poblanos on a sheet pan and broil on high, rotating frequently, until charred and blistered on all sides. Transfer immediately to a bowl, cover tightly with plastic wrap, and let sit 10 minutes.
- Use a paper towel to peel off the skins and absorb excess moisture. Cut each pepper lengthwise into 2 strips, discarding the stem and seeds. Blot dry.
- Preheat the oven to 350°F. Grease a 9×13-inch baking dish with nonstick spray.
- Heat the oil in a medium skillet over medium heat. Add the onion and cook until softened, 3 to 4 minutes. Add the garlic and cook 30 seconds. Remove from heat.
- Layer half the poblano strips in the bottom of the dish. Sprinkle with half the cheese and half the onion mixture. Repeat with the remaining peppers, cheese, and onions.
- In a large bowl, whisk the eggs, milk, flour, baking powder, cumin, salt, and pepper until completely smooth. Pour evenly over the casserole.
- Bake 35 to 40 minutes, until set in the center and golden brown on top.
- Let rest 10 minutes before slicing. Serve with sour cream, salsa, lime wedges, and chopped cilantro if desired.
Notes
- Blot the peppers dry: Excess moisture is the most common cause of a watery casserole.
- No broiler? Roast the peppers at 425°F for 15 to 20 minutes until blistered, or char them over an open gas burner, turning frequently with tongs.
- Hard to peel? The peppers were under-charred or under-steamed. Put them back under the broiler rather than scraping.
- Pepper size varies: Eight medium poblanos is the right amount. Use 10 if yours are small, 6 if they’re large.
- Short on time? Use four 7-ounce cans of whole green chiles instead. Drain well and blot with paper towels to avoid excess moisture.
- Monterey Jack melts best: Pepper jack adds heat, cheddar is the milder swap. Skip mozzarella and queso fresco; fresh mozzarella holds too much water and queso fresco doesn’t melt.
- Let it rest: Ten minutes out of the oven is what lets the egg finish setting for a clean slice.
- Make it ahead: Char, peel, and refrigerate the peppers up to 2 days early, and cook the onion and garlic at the same time. Don’t assemble the full casserole in advance.
- Leftovers: Keep covered in the fridge up to 3 days. This casserole is best the day it’s made. To reheat, bake uncovered at 350°F for about 20 minutes. Single portions need 30 seconds to 1 minute in the microwave.
- Freezing isn’t recommended: Poblanos lose their texture in the freezer and thaw out limp.
Nutrition
Nutritional Disclaimer Kristin Maxwell of “Yellow Bliss Road” is not a dietician or nutritionist, and any nutritional information shared is an estimate. For accurate calorie counts and other nutritional values, we recommend running the ingredients through your preferred online nutritional calculator. Calories and other nutritional values can vary depending on which brands were used.
