Muffin Kue Kopi

Bahan-bahan (6 porsi)

• scant 1 cup flour
• 1 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1/2 stick butter, room temperature
• 1/2 cup sour cream or plain yogurt
• 1/2 cup granulated sugar
• 1/2 teaspoon pure vanilla extract
• 1 egg
• 1/2 cup packed brown sugar
• 1/2 cup flour
• 1/2 teaspoon salt
• 1/2 teaspoon ground cinnamon (more to taste)
• 1/2 stick cold butter, cut into small pieces