Apple Cinnamon Streusel Muffins | Hy-Vee

Ingredients

• 2 cups all-purpose flour
• 1 teaspoon baking powder
• 1/4 teaspoon salt
• 3 tablespoons unsalted butter, softened
• 3/4 cup brown sugar
• 1 teaspoon ground cinnamon
• 1 large egg, beaten
• 3/4 cup milk
• 1 teaspoon vanilla extract
• 1 medium apple, peeled and grated
• 1/2 cup chopped walnuts (optional)