Streusel Ingredients:
1 1/4 cups all-purpose flour
1/3 cup packed dark brown sugar
1/3 cup sugar
1/2 teaspoon ground cinnamon
pinch of salt
7 tablespoons butter, melted
Muffin Ingredients:
4 tablespoons butter, melted and cooled slightly
2 cups flour
1 teaspoon vanilla
1 cup sugar
1 teaspoon lemon zest
1/2 cup buttermilk
1 tablespoon baking powder
1/2 teaspoon salt
1 1/2 cups frozen blueberries (keep in freezer until last possible moment)
1. For the streusel: combine flour, sugars, cinnamon, and salt in a bowl. Drizzle with melted butter and toss with a fork until evenly moistened and mixture forms chunks.
2. For the muffins: Adjust oven rack to middle position and preheat oven to 375. Either grease and flour muffin tin or use paper liners. Whisk egg in medium bowl until pale and evenly combined, 30 seconds. Add vanilla, sugar, and zest and whisk vigorously until thick, 30 seconds. Slowly whisk in melted butter, add buttermilk and whisk until combined.
3. Reserve 1 tablespoon flour. Whisk remaining flour, baking powder, and salt in large bowl. Fold in egg mixture until nearly combined. Toss blueberries with reserved flour and fold into batter until just combined.
4. Divide batter in muffin tin and top with streusel. Bake until light golden brown and toothpick inserted into center of muffin comes out with a few dry crumbs attached, 23-27 minutes. Cool muffins for 20 minutes in tin, the transfer to a rack to cool completely.
Makes 12 muffins
*recipe credit: Cook's Country