These are really good!

Blueberry Streusel Muffins
Source: My Mom

2 1/2 cups flour
1 1/2 cups sugar
1 Tbs. baking powder
1 cup butter
1/2 tsp. cinnamon
3/4 cup milk
2 eggs
1 1/2 tsp. vanilla
2 cups blueberries

Combine flour, sugar and baking powder. Cut in the butter. Remove 3/4 cup, adding the cinnamon to it and set it aside. Combine milk, eggs and vanilla. Fold into flour mixture. Stir in blueberries. Fill greased muffin cups 3/4 full. Sprinkle the set aside mixture onto the top of each muffin. Bake 30 minutes at 350F. (My oven takes only 25 min.)