Pistachio Blackberry Lava Cake

Ingredients

Volume measurements use US cups and level spoons and are approximate. Spoon flour and powdered sugar into the cup, level, then sift if directed. For cocoa and freeze-dried fruit powders, scoop the unsifted powder and level without packing, then sift if directed. Measure sprinkles loosely and level. Pack brown sugar. For ingredients marked "weigh for accuracy", use the listed grams.

Instructions

1. Prepare the pans and oven. Preheat the oven to 350°F. Grease three 8-inch round cake pans and line the bottoms with parchment paper.
2. Make the one-bowl cake batter. In a large bowl, whisk the sugar, oil, plain unsweetened yogurt, milk, apple cider vinegar, vanilla bean paste, and almond extract until fully smooth and emulsified.
3. Sift in the dry ingredients. Sift the cake flour, cornstarch, baking powder, baking soda, and salt directly into the wet ingredients. Whisk gently just until smooth. Do not overmix.
4. Divide and bake. Divide the batter evenly among the pans and tap them lightly to release air bubbles. Bake for 22-26 minutes, until the tops are set and a tester comes out clean or with a few moist crumbs.
5. Cool the cake layers. Let the cakes cool in their pans for 10-15 minutes, then turn them out onto wire racks and cool completely before assembly.
6. Make the pistachio lava. Heat the butter and cream together until fully melted and smooth. Whisk in the powdered sugar until smooth and glossy.
7. Add the fully stirred pistachio butter, corn syrup or glucose, vanilla bean paste, almond extract, and salt. Whisk until completely emulsified.
8. Let the pistachio lava stand until it reaches room temperature and is slightly thickened but still fluid and pourable.
9. Make the blackberry compote. Add the frozen blackberries and sugar to a saucepan over medium heat. Cook until the berries release their juices and begin to break down.
10. Continue cooking for 10-15 minutes, stirring occasionally and lightly mashing some berries while leaving some texture. Add the lemon juice and salt, then cook for 2-3 minutes more, until thick and glossy. Cool completely before assembly.
11. Make the vanilla pistachio buttercream. Beat the room-temperature butter for 3-5 minutes, until light and fluffy. Add the pistachio butter and beat until smooth.
12. Add the powdered sugar and mix for 5-7 minutes, until light and airy. Mix in the vanilla bean paste, almond extract, and salt. Slowly stream in the room-temperature cream and mix on low just until smooth.
13. Check the fillings before assembly. Make sure the cake layers and blackberry compote are completely cool and the pistachio lava is at room temperature, fluid, and not warm.
14. Build the first layer. Level the cake layers if needed. Place one layer on a cake board, spread a very thin layer of buttercream over it, and pipe a tall, unbroken buttercream dam around the edge.
15. Add the fillings. Pour a layer of pistachio lava inside the dam, keeping it below the top. Dot spoonfuls of blackberry compote over the lava, or gently spread a thin layer for a more even ribbon.
16. Repeat with the second cake layer, pistachio lava, and blackberry compote. Add the final cake layer and press gently to level.
17. Finish the cake. Apply a light crumb coat, chill briefly to set the structure, then finish with a thin layer of vanilla pistachio buttercream.