1-First Step: Prepare the blueberry filling. In a medium saucepan over medium heat, combine 2 cups fresh blueberries, 1/4 cup sugar, 1 tablespoon cornstarch, 1 teaspoon lemon zest, and 1 tablespoon lemon juice. Stir gently as it simmers for 5 minutes until thickened and bubbly. Berries will burst, creating a jammy texture. Remove from heat and let cool for 10 minutes. This prevents a runny filling that could soak the pastry. Tip: Fresh berries shine here, but frozen work too, just add 1 extra minute.

2-Second Step: Make the protein filling. In a small bowl, mix 1/2 cup plain Greek yogurt with 2 tablespoons vanilla protein powder until smooth. No lumps for even distribution. This combo adds creaminess and boosts protein without heaviness. Taste and adjust with a pinch of sugar if needed. Set aside. Pro move: Chill briefly for firmer texture during assembly.

3-Third Step: Prep the puff pastry. Unfold the thawed puff pastry sheet on a lightly floured surface. Cut into 9 equal squares (about 3×3 inches each). Use a sharp knife or pizza cutter for clean edges. Press gently on seams if any. Place squares on the prepared baking sheet, spacing 2 inches apart. This size holds filling perfectly without overflow.

4-Fourth Step: Assemble the pastries. Spoon 1-2 tablespoons cooled blueberry filling into the center of each square. Top with 1 tablespoon protein yogurt mixture. Fold opposite corners over the filling, pressing edges to seal. Or pinch all four corners to center for a pinwheel look. Handles vary for visual appeal. Avoid overfilling to keep them intact.

5-Fifth Step: Apply egg wash and bake. Whisk 1 large egg with 1 tablespoon water. Brush lightly over tops of pastries. This promotes even browning and shine. Bake in preheated oven for 15-20 minutes until puffed and golden. Rotate sheet halfway for uniform color. Cool on wire rack 5 minutes. They firm up as they cool.

6-Final Step: Add glaze and serve. Whisk 1/2 cup powdered sugar, 1-2 tablespoons milk, and 1/2 teaspoon vanilla until smooth. Drizzle over warm pastries. Serve fresh with coffee or yogurt. Pair with eggs for a full meal. Store extras as noted below. Each bite delivers flaky crust, juicy berries, and protein satisfaction.