In a medium bowl, beat the softened cream cheese with the granulated sugar, vanilla extract, lemon juice, and lemon zest until light and fluffy. Set aside.

In a small saucepan over medium heat, combine the fresh blueberries, 1 tbsp sugar, and lemon juice. Stir gently until blueberries begin to burst and release juices.

Stir in the cornstarch slurry and simmer for 1 minute until thickened. Remove from heat and let cool completely.

Lay one egg roll wrapper on a clean surface with a corner pointing toward you (diamond shape). Place about 2 tbsp cream cheese mixture in the center, then top with 1 tbsp cooled blueberry filling.

Fold the bottom corner up over the filling. Fold in the left and right side corners toward the center to form an open envelope. Brush the top corner with egg wash.

Roll the wrapper tightly toward the remaining corner and press to seal, ensuring no air pockets.

Fill a heavy-bottomed skillet with 2 inches of vegetable oil. Heat to 350°F (175°C). Test readiness by dipping a wooden spoon end into the oil; if it bubbles steadily, it's ready.

Gently add 3-4 egg rolls to the hot oil. Fry for 2-3 minutes per side until golden brown.

Remove with a slotted spoon and drain on a wire rack over paper towels to prevent sogginess.

While still warm, dust generously with powdered sugar. Serve immediately or as desired.