01 -
In a small mixing bowl, combine all-purpose flour, brown sugar, and ground cinnamon. Stir in melted unsalted butter until the mixture forms coarse crumbs. Set aside.
02 -
Preheat oven to 190°C (375°F). Line a 12-cup muffin tin with paper liners or lightly grease the cups.
03 -
In a medium bowl, whisk together all-purpose flour, baking powder, baking soda, and salt. Set aside.
04 -
In a large bowl, whisk granulated sugar, brown sugar, melted butter, eggs, and vanilla extract until smooth and homogenous.
05 -
Stir buttermilk into the wet ingredients, mixing until fully incorporated.
06 -
Gradually fold the dry mixture into the wet mixture, stirring gently just until combined. Avoid overmixing; some lumps are acceptable.
07 -
Gently fold diced strawberries into the batter, ensuring even distribution.
08 -
Divide the batter evenly among the muffin cups, filling each about three-quarters full.
09 -
Sprinkle the prepared streusel evenly over each portion of batter.
10 -
Bake in the preheated oven for 20 to 25 minutes, or until a toothpick inserted into the center of a muffin emerges clean.
11 -
Cool muffins in the tin for 5 minutes, then transfer to a wire rack to cool completely before serving.