Preheat oven to 350°F (177°C). Grease a 12-cup muffin tin very well or use silicone liners (paper liners can stick).
In a large bowl, whisk together all dry ingredients.
2 cups rolled oats, 1 cup instant oats, ¼ cup brown sugar, 2 teaspoons baking powder, 1 teaspoon ground cinnamon, 1 tablespoon vanilla protein powder
In a medium bowl, whisk the wet ingredients.
1 flax egg, 1 cup oat milk, ⅓ cup applesauce, 2 tablespoons olive oil
Pour the wet ingredients into the dry and stir until just combined—don’t overmix.
¾ cup fresh blueberries
Gently fold in the blueberries (and any optional add-ins). The batter will be looser than regular muffin batter; that’s normal.
Divide the mixture evenly among the 12 muffin cups (they will be almost full). If desired, press a few extra blueberries on top.
optional add-ins: ⅓ cup chopped nuts, a handful of white/chocolate chips, or lemon zest for brightness
Bake for 18 - 22 minutes, until the tops are set and lightly golden and a toothpick comes out clean (or with just a few moist crumbs).
Let cool in the pan for 5–10 minutes, then transfer to a wire rack. They firm up as they cool.