Apple Streusel Coffee Cake

Ingredients

• 2/3 cup packed brown sugar
• 0.5 cup all-purpose flour
• 1 teaspoon ground cinnamon
• 6 tablespoons cold butter
• 1 apple – peeled, cored, and chopped
• 1 cup chopped walnuts
• 2 cups all-purpose flour
• 1 tablespoon baking powder
• 1 teaspoon salt
• 1 cup white sugar
• 1/3 cup butter, softened
• 1 cup milk
• 1 large egg
• 1 teaspoon vanilla extract

Steps

1. Preheat the oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking pan.
2. Combine brown sugar, 1/2 cup flour, and cinnamon in a bowl. Cut in 6 tablespoons cold butter. Stir in apple and walnuts. Set streusel topping aside.
3. Combine 2 cups flour, baking powder, and salt in a bowl. Beat white sugar and 1/3 cup softened butter together in a large bowl with an electric mixer until creamy. Add baking powder mixture; stir in milk, egg, and vanilla extract. Transfer batter to the prepared pan; sprinkle streusel topping over top. Swirl a knife through both mixtures.
4. Bake in the preheated oven until a toothpick inserted into center comes out clean, 35 to 40 minutes.