Ingredients

  • cooking spray
  • 1 1⁄3 cups all purpose flour
  • 1 packed cup light or dark brown sugar
  • 2 teaspoons ground cinnamon
  • 1/2 teaspoon freshly grated nutmeg
  • 1/4 teaspoon fine sea salt
  • 1/2 cup unsalted butter, at room temperature
  • Cake:
  • 6 ounces unsalted butter
  • 1/2 cup granulated sugar
  • 1/4 packed cup light or dark brown sugar
  • 2 large eggs, at room temperature
  • 1 ½ teaspoons vanilla extract
  • 2 ¼ cups all purpose flour
  • 1 ½ teaspoons ground cinnamon
  • 1/2 teaspoon freshly grated nutmeg
  • 1 ½ teaspoons baking powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon fine sea salt
  • 3/4 cup buttermilk, at room temperature

Directions

  • Preheat the oven to 350 degrees F (180 degrees C) with an oven rack set in the center of the oven. Grease a 9-inch square pan with nonstick spray, and line the pan with parchment paper, allowing at least 2 inch of excess on each side (these will act as handles to make for an easier removal later).
  • To make the crumble topping: Stir flour, brown sugar, cinnamon, nutmeg, and salt together in a bowl until combined. Add butter and use your hands or a pastry cutter to mix until butter is fully incorporated, and mixture forms moistened clumps. It should no longer appear powdery. Set aside.
  • To make the coffee cake: Beat butter, sugar, and brown sugar in the bowl of an electric mixer fitted with the paddle attachment on medium speed until light and fluffy, 3 to 4 minutes.
  • Add eggs, 1 at a time, mixing well on medium speed to incorporate and scraping the bowl well after each addition.

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