Blueberry Muffins

Preheat over to 375 degrees F and line muffin pan with liners and set aside.
Beat softened butter and sugar together in a large mixing bowl. Beat in egg and vanilla. The mixture will be a bit lumpy, that's okay.
In a separate bowl, whisk together 1 1/2 cups of the flour, baking powder, and salt. Add the flour mix and buttermilk, alternating between the two 3 times until incorporated into the butter mix. Beat until completely combined.
In a small bowl, stir together about 1 cup of the blueberries and the extra tablespoon of all-purpose flour, make sure to coat. Gently fold blueberries into the batter. Add a 1/4 cup of batter to each muffin liner. Load up the tops of the muffins with remaining blueberries.

In a mixing bowl, use your hands to mix the crumble ingredients until it looks like, well... a crumble. Sprinkle crumble evenly over the tops of the muffins.
Reduce oven heat to 350 degrees F and bake muffins for 18-20 minutes.