Step 1: In a medium bowl, combine the softened cream cheese, granulated sugar, and vanilla extract. Mix with a spoon or rubber spatula until smooth and well combined.
Step 2: Gently fold in the fresh or frozen blueberries. Be careful not to mash them.
Step 3: Lay an egg roll wrapper on a clean, dry surface with one corner pointing towards you (like a diamond). Place about 1 ½ to 2 tablespoons of the blueberry cream cheese filling in the center of the wrapper, just below the middle.
Step 4: Fold the bottom corner of the wrapper up over the filling, tucking it in tightly. Then, fold in the left and right corners towards the center.
Step 5: Roll the egg roll upwards from the bottom, keeping it tight, until you reach the top corner. Dab a little whisked egg or water on the top corner to seal the egg roll completely.
Step 6: Repeat with the remaining wrappers and filling.
Step 7: Heat the vegetable oil in a large pot or deep skillet over medium-high heat until it reaches 350-375°F (175-190°C).
Step 8: Carefully place 2-3 egg rolls into the hot oil, ensuring not to overcrowd the pan. Fry for 2-3 minutes per side, or until golden brown and crispy.
Step 9: Remove the fried egg rolls with tongs and place them on a wire rack set over paper towels to drain any excess oil.
Step 10: Let cool slightly before serving. Optionally, dust with powdered sugar or drizzle with chocolate syrup for an extra touch of sweetness.