Melt the butter in a skillet over medium heat. Add the diced apples, brown sugar, and cinnamon, and cook for 5-7 minutes, stirring occasionally, until softened but not mushy.

Stir the flour or cornstarch into the water until smooth, then add it to the skillet. Cook for about 1 minute until the juices thicken, then remove the apple mixture from the heat and cool completely.

Beat the softened cream cheese, granulated sugar, vanilla, and optional cinnamon until smooth and creamy.

Place one wrapper in a diamond position. Add about 1 tablespoon of cream cheese filling and 1 tablespoon of apple filling to the lower center, fold the bottom corner over the filling, fold in the sides, and roll tightly. Moisten the final corner with water to seal.

Heat 4-6 cups of neutral oil to 350-360°F (175-182°C). Fry the egg rolls in small batches for approximately 2-4 minutes, turning once, until evenly golden and crisp.

Transfer the fried egg rolls to a wire rack or paper towels to drain. Dust with powdered sugar and serve warm with caramel sauce if desired.