Once your cakes have completely cooled, use a serrated knife to trim the tops if they have domed. This ensures your layers stack evenly and the finished cake looks neat.
Place a small dollop of buttercream in the center of your serving board or cake stand.
Set the first cake layer on the stand, bottom side down. Spread a generous, even layer of caramel buttercream over the top using an offset spatula. For extra flavor, drizzle a few spoonfuls of salted caramel sauce over the buttercream.
Carefully place the second cake layer on top, aligning it with the bottom layer. Press down lightly to secure the layers.
Spread a thin layer of buttercream over the entire cake to seal in any loose crumbs. Chill the cake for 15–20 minutes to let this crumb coat set before applying the final frosting.
Once chilled, apply a thick, even layer of caramel buttercream over the cake. Smooth it out with a spatula or cake scraper for a clean, professional finish.
Drizzle more salted caramel over the top, letting it drip slightly down the sides.
Let the cake sit at room temperature for 20–30 minutes before serving. This allows the buttercream to soften slightly, giving you the creamiest, most flavorful slices of your eggless apple cake.