Name: Salted Caramel Apple Crumble Cake
Prep time: 20 min
Total time: 4 h 40 min
Yield: 10 - 12 serving(s)
Ingredients: Cooking spray; 1 1/4 c. (250 g.) packed light brown sugar; 3/4 c. (1 1/2 sticks) unsalted butter, softened; 1/2 c. (100 g.) granulated sugar; 1/2 tsp. kosher salt; 1/4 c. neutral oil; 4 large eggs, room temperature; 2 tsp. baking powder; 2 tsp. pure vanilla extract; 1 tsp. ground cinnamon; 1/2 tsp. baking soda; 1/2 tsp. ground ginger; 1/2 tsp. ground nutmeg; 3/4 c. apple cider; 3 c. (360 g.) all-purpose flour, divided; 1/2 c. buttermilk; 4 tbsp. unsalted butter; 3 Granny Smith apples, peeled, cut into 1" cubes; 1/2 c. (105 g.) packed light brown sugar; 1/2 tsp. ground cinnamon; 2 tsp. cold water; 2 tsp. cornstarch; 1 1/4 c. (150 g.) all-purpose flour; 1/2 c. (100 g.) packed light brown sugar; 1/2 c. (1 stick) cold unsalted butter, cubed; 2 batches cream cheese frosting; 3/4 c. homemade or store-bought salted caramel sauce, divided

Spice Cake

Step 1Place a rack in center of oven; preheat to 350°. Grease 3 (8") round pans with cooking spray. Line pans with parchment.
Step 2 In the large bowl of a stand mixer fitted with the paddle attachment, beat brown sugar, butter, granulated sugar, and salt on medium-high speed until creamy and lightened in color, 2 to 3 minutes. Add oil and beat until incorporated.
Step 3Add eggs, one at a time, beating to blend after each addition. Add baking powder, vanila, cinnamon, baking soda, ginger, and nutmeg, and beat 45 seconds longer.
Step 4Add apple cider and one-third of flour and beat on low speed until just combined. Add another third of flour and buttermilk and beat until combined, then add remaining flour and beat just until no dry streaks remain. Divide batter among prepared pans (about 465 grams per pan).
Step 5Bake cakes until risen and springy to the touch and a tester inserted into the center comes out with moist crumbs attached, 22 to 28 minutes. Let cool completely before removing from pans.
Step 6Make Ahead: Cakes can be made 1 day ahead. Individually wrap cakes in plastic wrap and refrigerate.

Apple Filling

Step 1In a large pan over medium heat, melt butter. Stir in apples, brown sugar, cinnamon, and salt and bring to a simmer over medium-high heat. Reduce heat to medium and simmer, stirring occasionally, until the apples are just tender, about 10 minutes.
Step 2In a small bowl, whisk 2 teaspoons water and cornstarch. Pour slurry over apples and stir to incorporate. Return to a simmer and cook until slightly thickened, about 1 minute more. Let cool completely.
Step 3Make Ahead: Apple filling can be made 3 days ahead. Let cool, then store in an airtight container and refrigerate.

Crumble

Step 1In a medium bowl, whisk flour, brown sugar, and salt until combined. Add butter and toss until all butter cubes are coated in flour mixture.
Step 2With clean hands, continue to toss, smushing butter between your fingertips, until butter is flattened into large shards. Continue to toss, rubbing butter into finer and finer pieces, until mixture resembles coarse cornmeal and holds together in lumps if pressed.
Step 3Spread crumble mixture onto a parchment-lined baking sheet and freeze 10 minutes.
Step 4Preheat oven to 350°. Bake crumble from frozen 10 minutes. Remove from oven and toss with a heatproof spatula to redistribute. Continue to bake until lightly browned, 5 to 10 minutes more (crumble will crisp as it cools). Let cool.
Step 5Make Ahead: Crumble can be made 1 day ahead. Let cool, then store in an airtight container and refrigerate.

Assembly

Step 1If cream cheese frosting has been chilled, place in the large bowl of stand mixer fitted with the paddle attachment. Beat on medium-high speed until smooth and pliable, about 30 seconds.
Step 2Transfer 1 1/2 cups frosting to a piping bag fitted with a 1" round tip. Set remaining frosting aside.
Step 3If caramel sauce is cold and stiff, heat in the microwave in 15-second increments until smooth and pourable.
Step 4Using a serrated knife, level tops of cooled cakes. Discard (or eat!) trimmings.
Step 5Place 1 cake layer on a platter. Spread top with an even layer of frosting (about 3/4 cup). Pipe a ring of frosting around edge of cake, then pipe another ring of frosting directly on top of that ring, creating a tall dam to hold the fillings in. Fill with 1 cup apple filling. Sprinkle with 1/2 cup crumble. Drizzle crumble with 2 tablespoons caramel.
Step 6Place another cake layer on top. Spread top with an even layer of frosting. Pipe a double-stacked ring of frosting around edge of second layer as before. Fill with 1 cup apple filling, 1/2 cup crumble, and 2 tablespoons caramel. Place third cake layer on top smooth side up.
Step 7Frost top and sides of cake with a thin coat of frosting, then refrigerate at least 2 hours or up to overnight. Refrigerate remaining frosting.
Step 8When ready to finish, stir remaining frosting until smooth and pliable. Apply a clean layer of frosting over crumb coat. Drizzle with remaining 1/2 cup caramel, then top with remaining crumble.