1. In a medium bowl, mix 2 cups biscuit and baking mix and 1 cup packed light brown sugar, set aside.
2. In 2 cup glass measure, combine blueberry yogurt, eggs, butter, and vanilla.
3. Gently fold into dry ingredients until they are moistened.
4. Scoop about 1/4 cup of mixture into greased muffin tins.
5. Place fresh blueberries over top of each muffin.
6. Mix 1/3 cup biscuit and baking mix with 1/4 cup brown sugar and 3 tablespoons melted butter until crumbly. Sprinkle over top blueberries and bake. "