Step 1: In a medium bowl, gently combine the blueberries, 1/4 cup granulated sugar, cornstarch, lemon juice, and 1/2 teaspoon vanilla extract. Set aside.
Step 2: Unroll both refrigerated pie crusts onto a lightly floured surface. Using a 3-inch round cookie cutter or a glass rim, cut out as many circles as possible from each crust. You should get about 8 circles per crust. Re-roll scraps to cut additional circles if desired.
Step 3: Spoon about 1 tablespoon of the blueberry filling into the center of each pie crust circle. Lightly moisten the edges of half of each circle with water. Fold the other half over the filling to form a half-moon. Press firmly around the edges to seal, then use a fork to crimp the edges.
Step 4: Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper. Arrange the assembled pie bombs on the baking sheet. In a small bowl, whisk together the egg yolk and 1 tablespoon milk for the egg wash. Brush the tops of each pie bomb with the egg wash and sprinkle with the remaining 1 tablespoon granulated sugar.
Step 5: Bake for 15-20 minutes, or until golden brown and the filling is bubbly. Remove from oven and transfer to a wire rack to cool slightly while preparing the glaze.
Step 6: For the cream cheese glaze, combine the softened cream cheese, powdered sugar, 2 tablespoons milk, and 1/2 teaspoon vanilla extract in a medium bowl. Beat with an electric mixer or whisk until smooth and creamy. Adjust milk or powdered sugar to reach desired drizzling consistency.
Step 7: Once the pie bombs have cooled for about 10-15 minutes, drizzle generously with the cream cheese glaze. Serve warm and enjoy your Easy Blueberry Pie Bombs Cream Cheese Glaze!