Heat the oil in a large frying pan over medium-high heat.
Mix the pumpkin, flour, egg, milk, cheese, baking powder, salt, and pepper in a large bowl. Stir to combine well; the mixture should barely bind together and not be wet or watery.
Using a spoon, scoop up the pumpkin mixture and drop it gently into the hot oil. Fry in batches until both sides are golden brown and the inside is cooked through. Remove from the oil with a strainer and transfer the fritters to a plate lined with paper towels. Serve hot with Thai sweet chili sauce.
Notes
Use kabocha pumpkin or Japanese pumpkin if you can find it. Kabocha pumpkin is sweeter than regular pumpkin.