To make the streusel, combine the flour, brown sugar and cinnamon. Whisk together. Add the melted butter and stir with a fork until mixture is crumbly but not dry. Set aside.

Preheat oven to 400 degrees. Grease a 12 cup muffin pan with nonstick cooking spray or line with paper muffin liners. Set aside.

In a medium bowl, whisk together the flour, baking powder and salt. Set aside.

In a separate bowl, whisk the eggs and sugar until incorporated. Add the greek yogurt, melted butter and vanilla. Stir to combine well.

Add the wet ingredients to the dry ingredients and stir gently with a rubber spatula until barely combined. Stir in the blueberries, being careful not to over mix the batter.

Use a large ice cream or cookie scoop to divide the batter evenly between the 12 muffin cups, filling ¾ full.

Top with a generous amount of brown sugar streusel, pressing the streusel down gently onto each muffin.

Bake for 5-6 minutes at 400 degrees and then lower the oven temperature to 350 degrees. Bake for an additional 15-16 minutes for until a toothpick inserted into the center comes out clean or with a few crumbs remaining. Do not over bake.

Cool muffins in the pan on a wire rack for 10 minutes before carefully removing the muffins from the pan. Let muffins cool before adding the glaze.

Combine the confectioners sugar, milk, greek yogurt and vanilla in a medium bowl and whisk until smooth. If mixture is too thin, add more confectioners sugar. If too thick, add more milk. Once mixture is at desired consistency, drizzle over the tops of the cooled muffins.