Prep the pan and oven. Heat your oven to 350°F (175°C).
Line a 12-cup muffin tin with paper liners or lightly grease it.
Blend the wet ingredients. In a blender or food processor, add cottage cheese, eggs, maple syrup, oil, and vanilla. Blend until smooth and creamy, about 20–30 seconds. This step removes curds and creates a silky batter base.
Mix the dry ingredients. In a large bowl, whisk the flour, oat flour, protein powder, baking powder, baking soda, salt, and lemon zest until well combined.
Combine wet and dry. Pour the blended mixture into the dry ingredients.
Stir with a spatula until just combined. Do not overmix; a few small streaks of flour are fine.
Fold in the blueberries. Gently stir in the blueberries. If using frozen, keep them unthawed and toss them in 1 teaspoon flour first to minimize bleeding.
Fill the muffin cups. Divide the batter evenly among the 12 cups, filling each about 3/4 full.
Sprinkle tops with turbinado sugar if you like a subtle crunch.
Bake. Place the pan on the center rack and bake for 18–22 minutes, or until the tops are set and golden and a toothpick comes out clean or with a few moist crumbs.
Cool. Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely. This helps them set and prevents soggy bottoms.