Mix unsalted butter and granulated sugar together
Add room temperature eggs to the mixture
Combine baking powder and all-purpose flour
Alternate adding flour mixture and whole milk to the butter mixture
Fold in fresh blueberries
Prepare crumble by mixing flour, brown sugar, and cold butter
Pour batter into muffin cups and top with crumble
Bake at 425°F (220°C) for 5 minutes
Reduce temperature to 350°F (180°C) and continue baking for 15-20 minutes until golden and risen
