Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease.
In a large bowl, whisk together oat flour, protein powder, baking powder, baking soda, salt, and cinnamon.
In a separate bowl, whisk eggs, Greek yogurt, maple syrup, almond milk, coconut oil, and vanilla until smooth.
Pour wet ingredients into dry ingredients and stir until just combined. Do not overmix.
Gently fold in the blueberries.
Divide batter evenly among the muffin cups, filling each about three-quarters full.
Bake for 20–22 minutes, or until a toothpick inserted in the center comes out clean.
Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.