Prep your pan and oven. Heat the oven to 375°F (190°C).
Line a standard 12-cup muffin tin with paper liners or lightly grease it.
Mix the dry ingredients. In a large bowl, whisk flour, protein powder, baking powder, baking soda, salt, and cinnamon until evenly combined.
Whisk the wet ingredients. In a separate bowl, beat the eggs. Add Greek yogurt, milk, sugar, honey, oil, and vanilla. Whisk until smooth and no yogurt lumps remain.
Combine gently. Pour wet ingredients into the dry.
Stir with a spatula just until the flour disappears. The batter should be thick but spoonable. Do not overmix.
Prep the blueberries. Toss blueberries with 1 tablespoon flour to help prevent sinking. Fold them into the batter with a few gentle strokes.
Fill the tin. Divide batter evenly among the 12 cups, filling each about 3/4 full.
If you like, sprinkle a pinch of coarse sugar or a few sliced almonds on top for crunch.
Bake. Place the pan on the middle rack and bake for 16–20 minutes, or until the tops are set and a toothpick comes out with a few moist crumbs. Avoid overbaking to keep them tender.
Cool. Let muffins rest in the pan for 5 minutes, then transfer to a wire rack to finish cooling. They’ll firm up slightly as they cool.
Enjoy. Serve warm or at room temperature. They’re great plain or with a smear of almond butter.