Blueberry Streusel Muffins

Ingredients

• 1/4 cup butter, softened
• 1/3 cup sugar
• 1 egg
• 2 1/3 cups flour
• 3 t. baking powder
• 1/2 t. salt
• 1 cup milk
• 1 t. vanilla extract
• 1 1/2 cups blueberries
• 1/2 cup sugar
• 1/3 cup flour
• 1/2 t. ground cinnamon