Apple-Cinnamon Muffins with Walnut Streusel - Witten Kitchen

Ingredients

• 1 ¼ cup cake flour
• ½ tsp. baking soda
• ½ tsp. salt
• ½ cup (1 stick) unsalted butter
• 2 eggs + 2 egg whites
• 2 Tbsp. fat free Greek yogurt
• 2 apples, peeled, cored, and chopped into small ½-inch pieces
• 1 cup light brown sugar
• 1 tsp. cinnamon
• ½ tsp. vanilla extract
• ½ cup walnuts
• ¼ cup brown sugar
• ¼ cup AP flour
• ¼ tsp. salt
• 2 Tbsp. unsalted butter