Spiced Oatmeal Crumb Cake with Vanilla Oat Crumble

This recipe was generously shared with us by Lisa Balcom of The Unlisted Table. Lisa writes: 

There’s always a point toward the end of summer when my mind starts wandering toward fall. I’m not necessarily ready for full-on pumpkin and apple season, but suddenly I want oats, warm spices, brown sugar, and the kind of cake that practically demands a cup of coffee alongside it. This oatmeal spice crumb cake hits exactly that note. 

The oats add a chewy texture that makes this cake almost like a softer oatmeal cookie but with some irresistible crunch from the crumble. The warming spices make it hard to resist going back for another slice. Try it warm with a scoop of ice cream and a little drizzle of caramel for a super indulgent treat or enjoy a slice with your morning cup of coffee.

Together with her husband, Patrick, Lisa Balcom develops recipes and curates private dining experiences as the Unlisted Table in the Lexington, KY area. Lisa uses her background in pastry and bread baking to create a seasonal menu with thoughtfully sourced ingredients. 

Yield: 1, 8-inch cake

Total Time: 2 hours

Ingredients

Oatmeal Spice Cake

• 1 cup (90 g) Janie's Mill Oat Flakes (rolled oats)
• 3⁄4 cup (180 g) boiling water
• 1⁄2 cup (113 g) unsalted butter, softened
• 3⁄4 cup (150 g) granulated sugar
• 3⁄4 cup (150 g) packed light brown sugar
• 2 large eggs (about 100 g out of the shell), room temperature
• 2 teaspoons (8 g) vanilla extract
• 1 cup (120 g) Janie's Mill All-Purpose Flour
• 1⁄4 cup (30 g) Janie's Mill Oat Flour
• 1 teaspoon (6 g) baking soda
• 1 1⁄2 teaspoons (4 g) ground cinnamon
• 1 teaspoon ground ginger
• 1⁄2 teaspoon ground mace
• 1⁄2 teaspoon (3 g) fine sea salt

Vanilla Oat Crumble

• 3⁄4 cup (180 g) cold unsalted butter, cubed
• 1⁄2 cup (100 g) raw or turbinado sugar
• 1⁄3 cup plus 1 tablespoon (50 g) Janie's Mill All-Purpose Flour
• 1⁄4 cup (30 g) Janie's Mill Oat Flour 
• 1 cup (80 g) Janie's Mill Oat Flakes (rolled oats)
• 1⁄2 teaspoon (3 g) fine sea salt
• 1⁄2 vanilla bean, split and seeds scraped

Instructions

1. Preheat the oven to 350°F (175°C). Grease an 8-inch round baking pan and line with parchment paper if desired.
2. Soak the oats: Place the rolled oats in a bowl and pour the boiling water over them. Stir to combine and let the oats sit for about 20 minutes, until softened and hydrated. Set aside to cool while you prepare the crumble and cake batter.
3. Make the vanilla oat crumble: Combine the raw sugar, all-purpose flour, oat flour, rolled oats, and salt in a bowl. Scrape the seeds from the vanilla bean directly into the dry ingredients. Use your fingertips to rub the vanilla into the sugar, breaking up any clumps and distributing those tiny seeds throughout the mixture. 
4. Add the cold, cubed butter and work it into the dry ingredients until everything is thoroughly moistened and you have a mixture of small crumbs and larger, craggy pieces. Freeze the crumble while you make the cake batter. Keeping that butter cold helps the crumble hold onto its texture in the oven.
5. Make the cake: In the bowl of a stand mixer fitted with the paddle attachment, cream the softened butter, granulated sugar, and brown sugar until light and fluffy. Add the eggs one at a time, mixing well after each addition. Add the vanilla, scrape down the sides and bottom of the bowl, and mix again until everything is well incorporated.
6. In a separate bowl, whisk together the all-purpose flour, oat flour, baking soda, cinnamon, ginger, mace, and salt.
7. Alternate adding the dry ingredients and the cooled soaked oats to the butter mixture, mixing on low just until incorporated. Scrape down the bowl as needed and avoid overmixing.
8. Spread the batter evenly into the prepared pan.
   
9. Bake at 350°F (175°C) for about 55-65 minutes. After 25 minutes, scatter the cold vanilla oat crumble evenly over the cake until the entire surface is evenly covered. You should have a little crumble left over. Keep the crumble loose rather than pressing it into the batter. You want those irregular pieces to stay craggy and crisp as they bake. 
10. Return to the oven for another 30 to 40 minutes, or until the crumble is golden brown and a tester inserted into the center of the cake comes out clean or with just a few moist crumbs attached.
11. Allow the cake to cool before slicing.