5tablespoonscold unsalted butter, cut into small pieces
For the muffins:
2cupsall-purpose flour
1/2cupgranulated sugar
1/4cuppacked light brown sugar
1tablespoonbaking powder
1/2teaspoonground allspice
1/4teaspoonsalt
1stick (8 tablespoons) unsalted butter, melted and cooled
2large eggs
3/4cupwhole milk
1/4teaspoonvanilla extract
Instructions
Preheat oven to 375°F. Spray a standard muffin pan with nonstick cooking spray or line with paper liners.
For the streusel:
Using your hands, blend together the flour, brown sugar, and allspice in a small bowl. Add butter, a few pieces at a time, mixing with your hands to coat the butter in the dry ingredients. Once all the butter is added the mixture should be lumpy. Place in the refrigerator while preparing the muffins (can be covered and refrigerated for up to 3 days).
For the muffins:
Whisk together the flour, granulated sugar, brown sugar, baking powder, allspice, and salt in a large bowl, making sure there are no clumps. In a large glass measuring cup or small bowl whisk the butter, eggs, milk, and vanilla. Add mixture into dry ingredients and gently stir with a rubber spatula until mixture is combined but still lumpy.
Divide batter evenly among cups in prepared muffin pan. Sprinkle streusel over each muffin, gently pressing into the batter. Bake for about 20 minutes, or until the muffins are golden and a toothpick inserted into the center comes out clean. Allow muffins to cool in pan on a wire rack for 5 minutes before removing muffins to rack to cool completely.