Strawberry-Chocolate Chip Muffins with Chocolate Streusel Topping

Step 1
Preheat the oven to 400 degrees F (200 degrees C). Grease 18 cups of 2 standard 12-cup muffin tin or line cups with paper liners.

Step 2
Combine flour, brown sugar, white sugar, cocoa powder, and salt in bowl for the streusel topping until well combined. Mix in melted butter and vanilla until mixture resembles wet sand. Set aside.

Step 3
Mix together flour, baking powder, and salt for muffins in a large bowl until combined. Add strawberries and chocolate chips and stir until evenly distributed in the flour mixture.

Step 4
Whisk sugar, egg, and melted butter together in a bowl until thoroughly combined. Add buttermilk and vanilla extract and whisk until thoroughly incorporated. Add buttermilk mixture to the flour mixture and gently fold just until no dry clumps of flour remain. Do not overmix.

Step 5
Spoon batter into the prepared muffin cups and sprinkle streusel topping evenly over each muffin, about 1 to 1 1/2 tablespoons per muffin.

Step 6
Place pans into the preheated oven and bake until edges of the muffins are golden and tops spring back lightly when touched, 22 to 27 minutes. Allow muffins to cool in the pan for 10 to 15 minutes before carefully transferring them to a wire rack to cool completely.