Begin by adding the almond flour, oat flour, casein protein powder, baking powder, baking soda, your preferred granulated sweetener, and a small pinch of salt to a medium-sized mixing bowl. Use a whisk to mix everything thoroughly until the texture looks even and smooth. Breaking up any clumps now helps your muffins bake light and fluffy later.

In a separate bowl, whisk together the Greek yogurt, egg, melted butter, vanilla extract, and almond milk. Whisk until the mixture becomes completely smooth with no lumps of yogurt or streaks of egg remaining. This helps create a soft, creamy batter base.

Pour the bowl of wet ingredients into the bowl of dry ingredients. Using a spatula, fold the mixture slowly and gently until a thick, scoopable batter forms. Try not to stir too hard or too long—overmixing protein batters can make muffins dense or chewy. If the batter feels too thick to scoop, add a teaspoon or two of almond milk.

Add the blueberries to the batter and fold them in carefully with your spatula. Try to mix just until the berries are evenly distributed. This prevents the blueberries from bursting or turning the batter purple.

Prepare your muffin tray by lining it with parchment liners or lightly greasing each cup. Scoop the batter into 6–8 wells, filling each one about three-quarters full. If you enjoy a bakery-style look, sprinkle a few sliced almonds or extra blueberries on top of each portion.

Place the tray into a preheated 350°F (175°C) oven. Bake the muffins for 14–18 minutes, depending on your oven and muffin size. They’re ready when the tops turn lightly golden and a toothpick inserted in the center comes out clean. The muffins will continue to firm up as they cool, so avoid overbaking.

Allow the muffins to rest in the tray for about 10 minutes. This helps them set and makes them easier to remove. After that, transfer them to a cooling rack and let them finish cooling. Enjoy them warm, or let them cool completely before storing for an easy, high-protein meal prep breakfast.