Preheat your oven to 350°F (175°C) and line a muffin tin with six silicone or parchment liners.
Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
In a medium mixing bowl, whisk together the oat flour, vanilla protein powder, baking powder, sea salt, and monk fruit sweetener.
In a separate bowl, combine the nonfat Greek yogurt, egg whites, lemon juice, lemon zest, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined, being careful not to overmix the batter.
Gently fold in the fresh blueberries using a spatula to prevent them from bursting and turning the batter purple.
Divide the batter evenly among the six muffin liners, filling each about three-quarters of the way to the top.
Bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.