Salted-Caramel Six-Layer Chocolate Cake
If you don't own a candy thermometer, this cake offers a good excuse to buy one. It sounds a little nitpicky, but the caramel should reach exactly 238 degrees. (Any less and the cake layers won't hold together properly; any more and the caramel will turn hard.) Precision will also pay off with the chocolate frosting—it achieves its ideal spreading texture after standing for 30 minutes.
To make this cake ahead of time: The caramel can be refrigerated for up to 3 days; bring to room temperature before using. Cake layers can be refrigerated for up to 3 days (they actually taste better when refrigerated and have a better texture for stacking). When finished, the frosted cake can be refrigerated for up to 3 days.