Chocolate Cake with Salted Caramel Frosting

Make the salted caramel

1. Make sure you have all the ingredients for the caramel at the ready.
2. Spread the sugar evenly in a light-colored saucepan or deep skillet, which lets you monitor the sugar's color change, and crank the heat to medium-high.
3. As the pan heats, shake and swirl it often so the sugar heats evenly. Avoid stirring for the moment.
4. Once the sugar begins to clump, stir with a heatproof spatula. The sugar will go through various stages—all of them scary-looking! At first, it’ll look wavy, then chunky, then hopelessly like a pile of tan pebbles. Keep cooking.
5. Once melted, let the sugar turn amber (think of the color of an old penny) without stirring. Watch closely to prevent burning.
6. CAREFULLY pour in the cream a bit at a time, whisking continuously. ☞ TESTER TIP: The caramel will bubble furiously, so stand back while drizzling in the cream.
7. Boil the caramel for 1 minute, whisking until any stubborn hard bits of caramel melt.
8. Slide the pan off the heat and whisk in the butter, salt, and vanilla, until smooth.
9. Pour the salted caramel sauce into a heatproof bowl and let it sit at room temperature for an hour. Cover the bowl with plastic wrap, and leave it on the counter for 3 to 4 hours or overnight.

Make the salted caramel frosting

1. Whip the room-temperature caramel in the bowl of a stand mixer fitted with the whisk attachment, or with a handheld electric mixer on medium-high speed, until fluffy, 3 to 5 minutes.
2. Beat in the room-temperature butter, a piece at a time, until smooth and supple. (If your frosting curdles, see the FAQ above.) Add a pinch of sea salt, if desired.

Assemble and frost the cake

1. Place one cake layer on a turntable or cake plate. Plop about 3/4 cup of frosting on top and spread to the edge.
2. Crown with the second cake layer and plop 1 1/2 cups of frosting on top. Spread the frosting thinly over the top and sides of the cake with an offset spatula to create a crumb coat, which, as its name suggests, seals in crumbs!
3. Slide the cake in the fridge for 20 minutes to set.
4. Finish decorating the cake with the remaining frosting. Then...devour!