Preheat and prep: Heat your oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease it.
This helps the muffins release cleanly.
Mix dry ingredients: In a large bowl, whisk together the flour, oats, protein powder, baking powder, baking soda, salt, and cinnamon. Break up any clumps so the batter mixes evenly.
Whisk wet ingredients: In a separate bowl or large measuring cup, whisk the eggs, yogurt, maple syrup, milk, oil, and vanilla until smooth.
Combine: Pour the wet mixture into the dry ingredients. Stir with a spatula until just combined.
The batter should be thick but scoopable. Avoid overmixing.
Fold in chocolate chips: Gently fold in the mini chocolate chips. Save a small handful for the tops.
Fill the tin: Divide the batter evenly among the 12 muffin cups.
Sprinkle a few extra chips on each for a bakery-style look.
Bake: Bake for 15–18 minutes, or until the centers spring back when lightly pressed and a toothpick comes out with a few moist crumbs.
Cool: Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack. This prevents soggy bottoms and helps set the texture.
Serve: Enjoy warm, or let them cool completely before storing. They pair great with coffee, tea, or a cold glass of milk.