01 -
Set your oven to 375°F and get a muffin tray ready with paper liners.
02 -
Mix sugar, cinnamon, and flour in a small bowl. Stir in melted butter with a fork until you get crumbles. Chill it in the fridge.
03 -
Combine flour, baking powder, sugar, salt, and the citrus zest in a big bowl using a whisk.
04 -
In another large bowl, whisk together buttermilk, melted butter, and the egg. It might look split—don’t panic.
05 -
Pour the wet mix into the dry. Gently stir until it's just blended. A thick and bumpy texture is what you want. Avoid overmixing.
06 -
Carefully fold the blueberries into the batter. Don’t stir too much, or the batter will turn purple.
07 -
Using a scoop that holds about 3 tablespoons, portion the batter evenly into 12 muffin cups.
08 -
Grab the streusel from the fridge, break it apart with your fingers, and sprinkle over each muffin.
09 -
Bake for 28-30 minutes. Look for golden crumbs and a springy muffin top when pressed lightly.
10 -
You can eat them while warm, but they taste way better after cooling for 2 hours.