Prep the pan and oven: Heat oven to 350°F (175°C). Line a 9x9-inch baking pan with parchment, leaving overhang for easy lifting. Lightly grease the parchment.

Mix dry ingredients: In a large bowl, combine 2 cups rolled oats, 1/2 cup protein powder, 1/3 cup almond flour, 2 tablespoons ground flaxseed, 1 teaspoon baking powder, 1 teaspoon cinnamon, and 1/4 teaspoon salt. Stir well so the protein powder disperses evenly.

Whisk wet ingredients: In a separate bowl, whisk 3/4 cup Greek yogurt, 1/2 cup unsweetened applesauce, 2 large eggs, 1/4 cup maple syrup, 1 teaspoon vanilla, and 2 tablespoons melted coconut oil (or neutral oil) until smooth.

Combine: Pour the wet mixture into the dry. Stir until no dry streaks remain. The batter will be thick but spreadable. If it looks dry, add 2–3 tablespoons milk or water.

Fold in add-ins: Gently fold in 1 cup blueberries and 1–2 tablespoons chia seeds. If using nuts, fold in 1/3 cup chopped walnuts or almonds. Avoid overmixing to keep blueberries intact.

Spread and level: Scrape the batter into the prepared pan. Use a spatula to press it into corners and smooth the top. For extra texture, sprinkle a tablespoon of oats or nuts on top.

Bake: Bake 25–32 minutes, until the top is set, edges are lightly golden, and a toothpick in the center comes out mostly clean (a few moist crumbs are fine).

Cool completely: Let the pan cool on a rack for at least 30 minutes. Lift the slab out using the parchment and cool another 10 minutes before slicing into 9–12 bars.

Serve or store: Enjoy warm or at room temp. For grab-and-go, wrap bars individually after they’re fully cool.