Apple Streusel Muffins

Bahan-bahan (12 porsi)

• 2 tablespoons old fashioned rolled oats
• 2 tablespoons all purpose flour
• 1 tablespoon packed brown sugar
• 1 tablespoon unsalted butter, (melted)
• ½ teaspoon ground cinnamon
• 1 cup all purpose flour
• ½ cup whole wheat flour
• 2 teaspoons ground cinnamon
• 1½ teaspoons baking powder
• ½ teaspoon baking soda
• ¼ teaspoon kosher salt
• ¾ cup low fat buttermilk
• ½ cup packed brown sugar
• 2 tablespoons canola oil
• 1 tablespoon unsalted butter, (melted)
• 1 large egg, (lightly beaten)
• 1 to 2 medium (about 1¼ cups) Granny Smith apple, (peeled and diced)