Preheat the oven to 425° F.
Grease the muffin pan with non-stick oil spray or line with paper liners, set aside.
In a small saucepan over low heat, melt the butter or melt in the microwave for about 30 seconds on high. Set aside to cool.
In a large bowl, combine the flour, sugar, baking powder, baking soda, and salt. Mix well to combine.
Add the berries and mix gently to coat the berries with the flour mixture. I have used blueberries and chopped strawberries. You can use any combination of berries of your choice.
In a separate bowl, whisk together butter, sour cream, milk, and vanilla.
Add wet ingredients into dry and mix until just combined. Be gentle with berries.
Use the ice cream scoop to divide the batter evenly between the muffin tins. Fill each muffin tin all the way up to the top.
Sprinkle the crumble topping over the top.
Bake the muffins for 5 minutes at 425° F, and then, keeping the muffins in the oven, reduce the oven temperature to 350° F.
Continue baking for 16-18 minutes or until the cake tester inserted in the center comes out clean.
Remove the muffins from the oven and let them cool in the pan for 5 minutes. Then transfer onto a cooling rack and let them cool completely before serving.