In a medium bowl, whisk together the flour, baking powder, salt, and spices.
In a separate large bowl, add the pumpkin puree, milk, egg, melted butter, brown sugar, and vanilla. Whisk the mixture until smooth and combined.
Add in the flour mixture. Mix just until combined and no lumps remaining.
Fill a Dutch oven/cast iron pot with at least 2 inches of vegetable oil and heat on medium-high until it reaches 320-350°F.
Using a tablespoon or a cookie scoop, dollop the batter into the oil, cooking 4-5 at a time until deep golden brown.
Remove fritters from the oil with the spider tool and place on a tray lined with paper towels.
Dust the fritters with cinnamon powdered sugar.
Storing leftovers: Pumpkin fritters are best eaten soon after frying them. This gives you the best texture. But you can store leftover fritters for a day or two in an airtight container. Fritters will lose their texture when frozen, so freezing is not recommended.Make Ahead - If you want to prep the fritters in advance, you can make the batter ahead of time. Mix up the batter and cover the bowl with plastic wrap. Store in the fridge for up to 24 hours until ready to fry. I recommend bringing the batter back to room temperature before frying in the oil.