Ingredients

  • 1/2 pound/226 grams unsalted butter (2 sticks), at room temperature
  • 1 1/4 cups/250 grams granulated sugar
  • 1/4 cup/45 grams packed light brown sugar
  • 3 large eggs
  • 1 1/2 teaspoons vanilla extract
  • 3/4 cup/180 milliliters buttermilk
  • 13 cup/80 milliliters neutral oil, like canola or grapeseed
  • 1 1/2 cups/180 grams cake flour
  • 1 teaspoon baking powder
  • 1 teaspoon kosher salt

Method

  • Put all but 1 tablespoon of the butter and the sugars in the bowl of a stand mixer and cream with the paddle attachment at medium-high speed, until the mixture is smooth and pale, approximately 3 to 4 minutes.
  • Mix in the eggs and vanilla, then continue to mix for another 3 minutes, until fluffy.
  • Add the buttermilk and oil and mix briefly to combine.
  • Set the mixer to a very low speed and add the cake flour, baking powder and salt, mixing for a minute or so and scraping down the sides of the bowl once or twice, until the batter has just come together, with no lumps.
  • Use the remaining tablespoon of butter to grease the interior of a 4- to 6-quart slow cooker, then pour the batter into the pot.
  • Cover and cook on low for somewhere in the neighborhood of 4 to 6 hours, until the cake has set and is cooked through at the center.
  • To serve, run a knife around the edge of the slow cooker to loosen the cake and then carefully invert onto a platter, or simply spoon the cake out of the slow cooker.