1
Preheat the oven to 180°C and line a 12-cup muffin pan with paper liners.
2
Make the crumb topping by rubbing the flour, both sugars, and cold butter together with your fingers until crumbly. Set aside.
3
In a bowl, mix together the melted butter, sugar, eggs, buttermilk, Greek yogurt, and vanilla extract.
4
Add the flour, baking powder, baking soda, and salt. Mix briefly to form a batter.
5
Gently fold the blueberries into the batter, then divide the batter among the muffin cups, filling them about ¾ full.
6
Spread the crumb topping over the muffins.
7
Bake the muffins for 20 to 25 minutes, until they are golden brown and cooked through.
8
Let it cool for 10 minutes in the pan, then continue cooling on a wire rack.
