Brown Butter Apple Walnut Coffee Cake

With tart apples and a spiced crumb topping, this tender coffee cake is a warm slice of fall. Fragrant brown butter infuses the batter with a nutty flavor while a dash of apple pie spice adds the perfect seasonal combination of flavors, with cinnamon, nutmeg, allspice and ginger all in one container. To keep the apples from becoming mushy and add a hint of color to the cake, leave the skin intact before folding into the base of the cake alongside chopped walnuts.

Streusel Topping

1/2 cup all purpose flour

1/2 cup packed brown sugar

1 teaspoon apple pie spice or ground cinnamon

1/2 teaspoon salt

6 tablespoons cold unsalted butter, cubed

1/2 cup chopped walnuts

Coffee Cake

8 tablespoons unsalted butter, plus additional for greasing pan

1/2 cup granulated sugar

1/2 cup packed brown sugar

2 large eggs

1 teaspoon vanilla extract

1/2 cup plain full-fat Greek yogurt, room temperature

2 cups all purpose flour

1 teaspoon baking powder

1/2 teaspoon baking soda

1/2 teaspoon salt

2 teaspoons apple pie spice or ground cinnamon

2 medium firm, tart apples, cored and diced

3/4 cup chopped walnuts

For the streusel:

Place flour, brown sugar, apple pie spice and salt in a medium mixing bowl and stir to combine. Cut in the butter into the flour using a pastry cutter or fingertips until coarse crumbs form. Stir in the walnuts and set aside in the refrigerator while making cake.

For the cake:

Preheat oven to 350°F. Grease a 9-inch diameter cake pan or baking dish with butter and set aside.

Melt 8 tablespoons butter in a small saucepan set over low heat. Cook until the butter starts to turn a golden-brown color and has a nutty aroma, swirling the pan occasionally, about 5-7 minutes. Immediately remove pan from the heat and allow butter to cool slightly.

Place the browned butter, granulated sugar and brown sugar in a large mixing bowl and whisk until well combined. Add the eggs, one at a time, whisking well after each addition. Add the vanilla and yogurt and whisk again.

In a separate large mixing bowl, place the flour, baking powder, baking soda, salt and apple pie spice and stir to combine. Add the flour mixture to the butter-sugar mixture and stir just until combined. Add the apples and walnuts and fold in until evenly incorporated.

Pour batter into the prepared pan or baking dish and spread evenly. Sprinkle the streusel topping evenly over the batter. Place pan in preheated oven and bake until cake is golden brown, and a toothpick inserted into the center comes out clean or with a few crumbs, about 50-55 minutes. Allow the cake to cool for at least 15 minutes before slicing.