Ingredients

The following ingredients have 12 Servings
  • 6 tablespoons (3 ounces, 85g) unsalted butter (at room temperature)
  • 1 cup (200g) packed light brown sugar
  • 2 large eggs (at room temperature)
  • 1/2 teaspoon vanilla extract
  • 3/4 cup (75g) Graham cracker crumbs
  • 3/4 cup (75g) speculoos crumbs ((such as Lotus Biscoff cookies, see headnote))
  • 1/2 cup (70g) whole wheat flour
  • 1 teaspoon baking powder (preferably aluminum-free)
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1/2 teaspoon ground cinnamon
  • 1 cup (250ml) buttermilk
  • 2 teaspoons turbinado or coarse crystal brown sugar ((optional) - you could also use granulated sugar)
  • 1/4 teaspoon flaky sea salt (preferable) or kosher salt ((optional))

Instruction

  • Preheat the oven to 350ºF (180ºC). Butter a 9-inch (23cm) round cake pan (one that's around 2-inch/5cm deep) or springform pan, or spray the inside with non-stick spray. Line the bottom with a round of parchment paper if you'd like, for easier release.
  • In the bowl of a stand mixer fitted with the paddle attachment (or by hand in a large bowl and spatula) beat the butter and sugar until light and fluffy on high speed for about 3 minutes. Add the eggs one at a time, beating well before adding the next one and stopping the mixer scraping down the sides of the bowl to make sure everything gets incorporated. Mix in the vanilla.
  • In a medium bowl, mix together the Graham cracker and speculoos cookie crumbs along with the whole wheat flour, baking powder, baking soda, salt, and cinnamon.
  • Stir half of the crumb mixture into the beaten butter with the mixer at low speed (although I often do the final mixing by hand of cake batters to ensure they don't get overmixed and all the ingredients get incorporated), then stir in the buttermilk, then the remaining crumb mixture. Scrape the batter into the prepared cake pan and sprinkle the turbinado sugar and flaky sea salt over the top, if using. (I recommend it!)
  • Bake the cake until a toothpick inserted in the middle of the cake comes out clean, about 40 minutes. Let cake cool completely in the pan.