Preheat oven to 425°F. Grease 10 standard size muffin tins and line with cupcake liners. Set aside.
In a small mixing bowl, combine all the ingredients for the streusel, using a fork or a pastry cutter to stir together until the mixture resembles wet sand.
In a large mixing bowl combine the melted butter and granulated sugar, beating until combined. Add the eggs in one at a time. Add the greek yogurt, buttermilk, and vanilla extract.
Add 2 cups flour, baking powder, and salt. Mix until it begins to come together (not fully incorporated). Toss the blueberries with the additional two Tablespoons of flour. Fold the blueberries into the batter, mixing only until combined. Batter will be thick.
Scoop batter into prepared muffin tins, filling about 3/4 of the way. You can use a large cookie scoop or a 1/4 cup measure to keep things consistent.
Sprinkle the tops of each muffin with about 2 Tablespoons of the streusel mixture, pressing the streusel gently into the batter so it sticks.
Bake for 5 minutes at 425°F, then turn oven down to 375°F and bake for an additional 15 minutes, until muffins are golden brown and spring back to the touch.
Remove from oven and allow to cool for at least 15 minutes before eating!
Notes
If you don’t have melted butter, you can sub out oil!
Don’t have buttermilk on hand? Make a homemade substitution with just two ingredients!
If you using frozen blueberries, do NOT over mix the batter. This will prevent any bleeding of the blueberry juices into your batter