Step 1

Preheat oven to 400 degrees F. Line a muffin pan with paper muffin cups or spray with nonstick cooking spray. Set aside.

Step 2

To make the streusel: Combine the flour, brown sugar, and butter pieces in a small bowl. Mix in the butter with your fingers or a pastry cutter until you have a crumb mixture. Place the streusel in the refrigerator until ready to use.

Step 3

To make the muffins: In a large bowl, whisk together the flour, sugar, baking powder, and salt. Add the brown sugar and whisk again until there are no brown sugar clumps.

Step 4

In a small bowl, combine the melted butter, eggs, buttermilk, and vanilla. Whisk until eggs are well combined with the other liquid ingredients.

Step 5

Pour the liquid ingredients over the dry ingredients and gently stir together with a spatula. Don't over mix the batter, stir just until flour disappears. In a small bowl, combine 1 cup of the blueberries with 1 tablespoon of flour and toss until blueberries are coated. Gently fold in 1 cup of the blueberries, being careful not to over mix.

Step 6

Divide the muffin batter evenly among the muffin cups. Top each muffin with remaining 1/4 cup blueberries, pressing them gently into the tops. Remove the streusel from the refrigerator and sprinkle evenly over each muffin. Gently press the crumbs into the batter.

Step 7

Bake the muffins for 18 to 20 minutes or until the muffin tops are golden and the tops are set. You can insert a toothpick into the center of a muffin and if it comes out clean, they are done.

Step 8

Transfer the pan to a cooling rack and let the muffins cool for 5 minutes in the pan. Remove from the pan and enjoy!