Oatmeal Cookie Dough Lava Cake

Instructions

1. 1Make the oatmeal cake. Preheat the oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper.
2. 2Blend the 90 g rolled oats in a high-speed blender or food processor until they resemble a fine flour with no large flakes remaining.
3. 3In 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.
4. 4Add 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.
5. 5Slowly stream in the hot milk while whisking gently. Stop as soon as the batter is smooth and glossy; do not overmix.
6. 6Divide the batter evenly between the prepared pans by weight and gently tap each pan once or twice to release large air bubbles.
7. 7Bake 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.
8. 8Cool 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.
9. 9Make 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.
10. 10Add 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.
11. 11Flatten 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.
12. 12Make 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.
13. 13Bring the mixture to a gentle simmer. Slowly whisk in the heavy cream, then simmer for 2–3 minutes, stirring frequently, until smooth and glossy.
14. 14Remove 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.
15. 15Stir 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.
16. 16Make the vanilla buttercream. Beat the softened butter for 2–3 minutes, scraping the sides of the bowl, until light and creamy.
17. 17Add the powdered sugar and vanilla bean paste. Mix on low until incorporated, then mix on medium just until smooth.
18. 18With 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.
19. 19Assemble 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.
20. 20Spread 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.
21. 21Place the second cake layer on top and repeat the thin buttercream layer, sturdy dam, caramel, and cookie dough. Top with the final cake layer.
22. 22Apply 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.
23. 23Before serving, finish the top with remaining caramel lava and additional chilled oatmeal cookie-dough pieces. Keep any extra caramel on the side for serving.