You are here: Home » Recipes » Apple-Streusel Muffins Apple-Streusel Muffins Recipe by California Walnut Board Yield 18 servings Prep 20 mins Cook 20 mins PrintEmail Ingredients Topping1/2 cup chopped California walnuts1/4 cup all purpose flour3 tablespoons granulated sugar2 tablespoons butter or margarine, at room temperature1/4 teaspoon ground cinnamonBatter1-1/2 cup all purpose flour1/2 cup granulated sugar2 teaspoons baking powder1 teaspoon ground cinnamon1/4 teaspoon baking soda1/4 teaspoon salt2 large eggs1 cup sour cream1/4 cup margarine, melted1 cup diced unpeeled apple, preferably a tart one such as Granny Smith Instructions Heat oven to 375F. Grease 18 regular-size muffin cups. Put Topping ingredients into a medium sized bowl. Mix with a fork, then crumble with your fingers until mixture resembles coarse crumbs. To prepare batter, mix flour, sugar, baking powder, cinnamon, allspice, baking soda, and salt in a large bowl until thoroughly blended. Break eggs into another bowl; add sour cream and melted butter and whisk until well blended. Stir in diced apple. Pour egg mixture over flour mixture and fold until dry ingredients are moistened. Spoon batter into muffin cups. Top each with a generous portion of topping. Bake 20 minutes or until browned and a wooden pick inserted into the middle comes out clean. Remove from pans and cool at least 1 hour.