Preheat the oven to 350 degrees. Prepare muffin tin by spraying with cooking spray.

In a small bowl, make the streusel. Stir together all the flour, sugar, salt, and ginger. Then cut the butter into flour mixture with a pastry cutter. I usually end up quickly rubbing the butter in a but more by hand until mixture is very fine and sandy. Pick up the streusel mixture by handfuls and give it a squeeze to form small clumps. Set aside.

Next, make the muffin batter in a medium bowl, by first whisking together the flour, baking powder and salt.

In a large bowl, stir together melted butter, sugar and egg until combined. Stir in half the flour mixture, followed by the buttermilk and vanilla. Stir in remaining flour mixture, mixing just until the dry ingredients are incorporated and no streaks of flour remain.

Gently fold in raspberries (toss frozen berries in 2 teaspoons of flour to keep them from “bleeding” into the muffin batter).

Divide muffin batter evenly into the prepared muffin pan. Cups will be fairly full. Divide streusel mixture over the muffins (be generous!).

Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out with only a few moist crumbs attached. Cool completely then store in an airtight container.