Preheat your oven to 350°. In a large bowl, whisk together eggs, maple syrup, vanilla, and plain Greek yogurt. Whisk until no chunks of yogurt remain and everything is smooth.
Add baking powder, baking soda, cinnamon, oats, milk, apple cider vinegar, and protein powder and stir until well combined. Let batter sit for 2-3 minutes to allow baking soda and vinegar to react. The batter will look bubbly, that’s okay!
Add whole wheat pastry flour and mix until just combined, try not to overmix.
Fold in blueberries, then divide evenly between 12 lined muffin cups. Fill each muffin cup completely full. Sprinkle the remaining ¼ cup oats evenly onto the 12 muffins.
Bake for 23-25 minutes or until a toothpick inserted in the center of the muffins comes out clean with no crumbs.