Coffee Cake Muffins

Ingredients

• unsalted butter, melted
• granulated sugar
• eggs, room temperature
• sour cream
• buttermilk
• teaspoons vanilla extract
• all purpose flour
• Tablespoon baking powder
• teaspoon salt
• brown sugar
• teaspoons ground cinnamon
• of salt
• Tablespoons butter, melted
• powdered sugar
• teaspoon vanilla extract
• Tablespoons milk