- 1/4 cup plus 2 tablespoons packed light brown sugar
- 2 tablespoons all-purpose flour
- 1/8 teaspoon cinnamon
- Pinch of kosher salt
- 2 tablespoons cold unsalted butter, diced
- 2 tablespoons old-fashioned rolled oats
- 2 tablespoons chopped pecans (optional)
- 1 1/2 cups all-purpose flour
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon cinnamon
- 1/4 teaspoon freshly grated nutmeg
- 1 stick unsalted butter, at room temperature
- 1 1/2 cups packed light brown sugar
- 3/4 teaspoon kosher salt
- 1 cup sour cream, at room temperature
- 2 large eggs, at room temperature
- 1/2 teaspoon pure vanilla extract
How to make this recipe
Preheat the oven to 350°. Coat a 9-inch-square cake pan with vegetable oil spray.
Make the crumbs
In a food processor, pulse the brown sugar with the flour, cinnamon and salt. Add the butter and pulse until the mixture has a sandy texture. Add the oats and pecans and pulse until incorporated. Transfer the crumbs to a bowl and freeze until ready to use.
Make the cake
In a medium bowl, combine the flour with the baking powder, baking soda, cinnamon and nutmeg. Sift the mixture onto a sheet of parchment paper.
In a large bowl, using an electric mixer, cream the butter with the brown sugar and salt at medium-high speed until fluffy, about 5 minutes; scrape the bowl. Add the sour cream and beat until smooth, about 2 minutes. Beat in the eggs one at a time at medium speed, scraping the bowl after each addition. Beat in the vanilla. At low speed, beat in the flour mixture in 3 additions, scraping the bowl as needed.
Spread the batter in the prepared pan and scatter the frozen crumbs on top. Bake for 30 minutes, until golden brown and a toothpick inserted in the center comes out clean. Transfer to a wire rack and let cool. Cut into 12 squares and serve warm or at room temperature.
The crumbs can be frozen in an airtight container for up to 1 week. The cake can be kept at room temperature for up to 3 days.