In a bowl, combine the melted butter, flour, and sugar for the crumble topping. Mix until combined and set aside.
3
In a large mixing bowl, cream together the butter and sugar for about 2 minutes until fully combined.
4
Add the eggs one at a time, mixing well after each addition.
5
Add the yogurt, milk, and vanilla, and mix again until incorporated.
6
Sift in the flour, baking powder, and salt. Mix just until combined—do not overmix.
7
Gently fold in the blueberries (fresh or frozen). Be careful not to overmix, as this can cause the berries to bleed color into the batter.
8
Place muffin liners in a muffin pan. This recipe yields 6 large muffins or 12 standard muffins.
9
Divide the batter equally among the muffin cups.
10
Top each muffin with the crumble topping.
11
Bake in the preheated oven at 205°C for 5 minutes, then lower the temperature to 180°C (350°F) and bake for an additional 30 minutes, or until a toothpick inserted in the center comes out clean.
12
Remove from the oven and let the muffins cool completely.