Obsessed Cakes
Oatmeal Cookie Dough Lava Cake
Soft oatmeal cake layered with brown sugar caramel lava, oatmeal cookie dough, and fluffy vanilla buttercream.
- Prep
- 1 hr
- Bake
- 22–27 min
- Total
- About 3 hr, including cooling and chilling
- Yield
- One 3-layer 8-inch cake
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Ingredients
Oatmeal Cake
- 210 g (about 1 3/4 cups) cake flour
- 90 g (about 1 cup) old-fashioned rolled oats, blended into a fine flour
- 2 teaspoons baking powder
- 1 teaspoon baking soda
- 8 g (about 1 tablespoon + 1/2 teaspoon) cornstarch
- 3/4 teaspoon fine sea salt
- 250 g (about 1 cup + 3 tablespoons) light brown sugar (packed)
- 230 g (about 3/4 cup + 3 tablespoons) milk, room temperature
- 15 g (about 1 tablespoon) apple cider vinegar
- 140 g (about 1/2 cup + 2 tablespoons) neutral oil
- 120 g (about 7 tablespoons + 2 1/2 teaspoons) plain unsweetened yogurt, room temperature
- 2 1/2 teaspoons vanilla bean paste
- 1/4–1/2 teaspoon butter extract
- 130 g (about 1/2 cup + 2 teaspoons) hot milk
Oatmeal Cookie Dough
- 113 g (about 1/2 cup) butter, softened
- 100 g (about 7 tablespoons + 1 1/2 teaspoons) light brown sugar (packed)
- 40 g (about 3 tablespoons + 3/4 teaspoon) granulated sugar
- 120 g (about 1 cup) all-purpose flour, prepared and cooled as noted
- 60 g (about 2/3 cup) old-fashioned rolled oats, blended into a fine flour
- 1 1/2–2 teaspoons vanilla bean paste
Brown Sugar Caramel Lava
- 170 g (about 3/4 cup + 2 teaspoons) light brown sugar (packed)
- 40 g (about 2 tablespoons + 2 teaspoons) water
- 85 g (about 6 tablespoons) butter
- 120 g (about 1/2 cup) heavy cream
- 20 g (about 3 tablespoons + 2 teaspoons) old-fashioned rolled oats
- 1 teaspoon vanilla bean paste
- 1/4 teaspoon fine sea salt
Vanilla Buttercream
- 270 g (about 1 cup + 3 tablespoons) butter, softened
- 450 g (about 3 3/4 cups) powdered sugar, sifted
- 80–100 g (about 1/3 cup to 6 tablespoons + 2 teaspoons) heavy cream, room temperature or slightly warm
- 2 teaspoons vanilla bean paste
Instructions
- Make the oatmeal cake. Preheat the oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper.
- Blend the 90 g rolled oats in a high-speed blender or food processor until they resemble a fine flour with no large flakes remaining.
- In a large bowl, whisk together the brown sugar, room-temperature milk, apple cider vinegar, oil, yogurt, vanilla bean paste, and 1/4 teaspoon butter extract until completely smooth and emulsified. Add up to 1/4 teaspoon more butter extract if desired.
- Add the cake flour, oat flour, baking powder, baking soda, cornstarch, and salt directly to the bowl. Whisk gently until mostly combined and no large pockets of flour remain.
- Slowly stream in the hot milk while whisking gently. Stop as soon as the batter is smooth and glossy; do not overmix.
- Divide the batter evenly between the prepared pans by weight and gently tap each pan once or twice to release large air bubbles.
- Bake for 22–27 minutes, beginning to check at 22 minutes. The layers are done when the centers spring back lightly and a toothpick inserted into the center comes out with a few moist crumbs and no wet batter.
- Cool the layers in the pans for 10 minutes, then turn them onto wire racks and cool completely. Once fully cool, wrap and refrigerate the layers until assembly.
- Make the oatmeal cookie dough. Beat the softened butter, brown sugar, and granulated sugar for 2–3 minutes, scraping the bowl as needed, until light and fluffy.
- Add the vanilla bean paste and mix until fully incorporated. Add the prepared flour and the 60 g finely blended oats, then mix on low just until a cohesive dough forms.
- Flatten the dough into a shallow covered container and freeze for 15–20 minutes, until firm enough to handle. Break it into irregular pieces about 1/2 inch wide, then refrigerate until assembly.
- Make the brown sugar caramel lava. In a medium saucepan, combine the brown sugar, water, and butter. Cook over medium heat, stirring frequently, until the butter melts and the sugar dissolves.
- Bring the mixture to a gentle simmer. Slowly whisk in the heavy cream, then simmer for 2–3 minutes, stirring frequently, until smooth and glossy.
- Remove from the heat and immediately stir in the rolled oats. Let the caramel rest for 10 minutes, stirring once halfway through, so the oats soften slightly.
- Stir in the vanilla bean paste and salt. Transfer to a heatproof container and refrigerate until completely chilled before assembly; the caramel will thicken as it cools.
- Make the vanilla buttercream. Beat the softened butter for 2–3 minutes, scraping the sides of the bowl, until light and creamy.
- Add the powdered sugar and vanilla bean paste. Mix on low until incorporated, then mix on medium just until smooth.
- With the mixer on low, slowly stream in 80 g of the cream. Add more only as needed, a little at a time, until the buttercream is light, smooth, and sturdy enough to hold a filling dam. Do not overmix.
- Assemble the cake. Place the first cold cake layer on a cake board or serving plate. Spread a very thin layer of buttercream over the cake, then pipe a tall, continuous buttercream dam around the edge.
- Spread chilled brown sugar caramel lava inside the dam, keeping it below halfway up the dam. Scatter chilled oatmeal cookie-dough pieces evenly over the caramel without overfilling the layer.
- Place the second cake layer on top and repeat the thin buttercream layer, sturdy dam, caramel, and cookie dough. Top with the final cake layer.
- Apply a thin crumb coat and refrigerate for 20 minutes. Frost the cake with the remaining vanilla buttercream, then chill for 20–30 minutes to set the structure.
- Before serving, finish the top with remaining caramel lava and additional chilled oatmeal cookie-dough pieces. Keep any extra caramel on the side for serving.
Helpful notes
- Heat-treat the flour to 165°F, then let it cool completely before making the cookie dough.