Coffee Cake Muffins

Ingredients

• 1 cup Granulated sugar
• 1 1/2 cups All purpose flour
• 1/2 cup dark brown sugar packed
• 1 tablespoon Cinnamon ground
• 1/2 teaspoon Baking powder
• 1/4 teaspoon Baking soda
• 1/2 teaspoon salt
• 12 tablespoon Unsalted butter cut into 1" pieces and chilled
• 3 whole eggs large
• 1/2 cup Sour cream
• Confectioners Sugar