Ingredients
- 2 ½ cups (313g) reclamation gluten-free pastry flour
- 1 ½ tsp (7.5g) baking powder
- ¾ tsp (4.7g) table salt
- ¾ cup (180g) whole milk, room temperature
- ½ cup (120g) sour cream, room temperature
- 8 tbsp (114g) unsalted butter, room temperature
- 1 cup (200g) granulated sugar
- ¼ cup (55g) light brown sugar
- 2 large (100g) eggs, room temperature
- 1 ½ tsp (7.5g) vanilla extract
Streusel Topping
- ⅔ cup (133g) granulated sugar
- ¼ tsp (1.6g) table salt
- ⅔ cup (84g) reclamation gluten-free pastry flour
- 2 tsp (4g) ground cinnamon
- 4 tbsp (57g) unsalted butter, cold, cubed
Cinnamon Filling
- ⅔ cup (147g) light brown sugar
- 1 tbsp (6g) ground cinnamon
Directions
Make the Topping
Add the sugar, salt, pastry flour, and cinnamon to a food processor, and process until well combined. Add the cold butter and pulse until well combined and clumps start to form. Chill the topping in the fridge until ready to use.
Make the Cinnamon Filling
Whisk together the brown sugar and cinnamon in a small bowl. Set aside.
Step 1
Preheat oven to 350°F, with the oven rack in the center position. Line a 9 x 9-inch square cake pan with parchment paper, and butter the parchment paper.
Step 2
In a medium bowl, whisk together the pastry flour, baking powder, and salt until well combined. Set aside. In a glass measuring cup, whisk together the milk and sour cream until combined.
Step 3
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld mixer, beat together the butter, granulated sugar, and light brown sugar on medium speed until well combined, about 1 - 2 minutes.
Add the eggs one at a time, mixing on medium speed until mostly combined after each. Add the vanilla and mix until combined.
Step 4
Add the flour mixture in 3 additions, alternating with 2 additions of the sour cream mixture, mixing on low speed just until combined after each. Begin and end with the flour mixture. Give the batter a final stir by hand, gently folding to ensure everything is fully combined.
Let the batter rest on the counter for 10 minutes, to give the pastry flour blend time to fully hydrate.
Step 5
Spread half of the batter into the prepared pan, smoothing the top with an offset spatula. Evenly sprinkle the cinnamon filling over the batter, then carefully spread the remaining batter on top.
Sprinkle the streusel topping over the top of the batter, making sure to evenly cover all the way to the edges.
Bake for 45 - 50 minutes, or until the cake is a deep golden brown color and the internal temperature registers about 208°F - 210°F. Cool in the pan for at least 20 minutes before serving.
