If making homemade caramel, I recommend making at least an hour before (or up to a week before) making the cake to give it time to cool down and thicken up.




Start with an extra couple tablespoons of butter, since water evaporates as it browns. Also, keep in mind that European-style butter has less water content, so if you're using American-style butter you might want to start with even more butter.




Don't add ingredients to the hot brown butter. Chill it in the fridge for about 15 minutes to bring it to room temperature before proceeding with the recipe.
Be sure to cut your apples into equally thin slices, so they will cook at the same rate.




I used honeycrisp apples, but you could also use another baking apple, such as granny smith or pink lady.