Ingredients:

  • 1/2 cup (100g) all-purpose flour, plus more for dusting the pan
  • 1/4 cup (50g) granulated sugar
  • 1/4 cup (50g) packed light brown sugar
  • 1/4 teaspoon kosher salt
  • 1/2 cup (113g) cold unsalted butter, cut into cubes
  • 1 tablespoon (8g) instant espresso powder
  • 1/4 cup (25g) chopped walnuts or pecans (optional)
  • 1 3/4 cups (210g) all-purpose flour
  • 1 teaspoon baking powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon kosher salt
  • 1/2 cup (113g) unsalted butter, softened
  • 3/4 cup (150g) granulated sugar
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 1/2 cup (120ml) strongly brewed coffee, cooled or 2 shots of espresso
  • 1/2 cup (120ml) sour cream

Instructions:

  1. Prepare the Streusel: Combine dry streusel ingredients in a bowl. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Stir in nuts, if using. Refrigerate until ready to use.
  2. Prep the Cake Pan: Grease and flour a 9-inch springform pan (or 8x8 pan).
  3. Combine Dry Ingredients: Whisk together flour, baking powder, baking soda, and salt in a bowl.
  4. Cream Butter and Sugar: Cream together the softened butter and granulated sugar until light and fluffy.
  5. Add Eggs and Vanilla: Beat in the eggs one at a time, then stir in the vanilla extract.
  6. Alternate Wet and Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, alternating with the coffee and sour cream, beginning and ending with the dry ingredients. Mix until just combined. Do not overmix.
  7. Pour into Pan: Pour the batter into the prepared pan and spread evenly.
  8. Top with Streusel: Sprinkle the chilled streusel evenly over the batter.
  9. Bake: Bake in a preheated oven at 350°F (175°C) for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
  10. Cool: Let cool in the pan for 10-15 minutes before removing to a wire rack to cool completely.