- 1
- 15 mins
- 55 mins
Ingredients
- Crumble topping
- 8 tablespoons (112 g) unsalted butter, melted
- 1/3 cup (73 g) packed light brown sugar
- 1/4 cup (50 g) granulated sugar
- 1 cup (140 g) all purpose gluten free flour (I used Better Batter)
- 1/2 teaspoon xanthan gum (omit if your blend already contains it)
- 1/8 teaspoon kosher salt
- Cake
- 1 3/4 cups (245 g) all purpose gluten free flour (I used Better Batter)
- 1 teaspoon xanthan gum (omit if your blend already contains it)
- 2 tablespoons (18 g) cornstarch
- 3/4 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon kosher salt
- 2 teaspoons ground cinnamon
- 6 tablespoons (84 g) unsalted butter, at room temperature
- 2 tablespoons (1 fluid ounce) milk, at room temperature
- 1 cup (256 g) sour cream, at room temperature
- 2 eggs (100 g, weighed out of shell) at room temperature, beaten
- 3/4 cup (150 g) granulated sugar
Preparation
Step 1
Preheat your oven to 350°F. Line an 8-inch square baking pan with parchment paper and set it aside.
First, prepare the topping. In a medium-size bowl, place all of the ingredients in the order listed, mixing to combine after each addition. Place the bowl in the refrigerator to chill until firm.
Make the cake batter. In a medium-size bowl, place the flour, xanthan gum, cornstarch, baking powder, baking soda, salt and cinnamon, and whisk to combine well. Set the bowl aside. In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, place the butter, milk and sour cream, and beat on medium speed to combine. Add the eggs and sugar, and beat to combine well. Add the dry ingredients to the bowl of wet ingredients and mix on medium high speed until well-combined. The batter will be very thick, since our liquid is mainly sour cream.
Scrape the batter into the prepared pan and smooth into an even layer with a wet spatula. Remove the chilled crumble topping from the refrigerator, fluff it with a fork to break up the mixture into irregular pieces. Scatter the pieces evenly on top of the cake batter and press down gently to help the topping adhere to the batter. Place the cake pan in the center of the preheated oven. Bake until the cake is fragrant and the center does not jiggle in the center when the pan is shaken from side to side gently and a toothpick inserted into the center comes out mostly clean, about 40 minutes. Do not overbake or the bottom will burn.
Allow to cool in the pan for about 10 minutes before lifting the cake out of the pan with the parchment paper. Slice into squares and serve.