The cake can also be topped with a simple glaze: Whisk together 1 cup confectioners' sugar and 2 tablespoons milk until smooth, then drizzle the mixture over the cooled cake; let set 20 minutes before serving.
Purple kale or curly kale can be substituted for the Tuscan variety (also called lacinato); chop the sturdy leaves instead of tearing them. Spelt is a good alternative to farro, with a similar taste and texture. We prefer French feta, which is typically milder and creamier, to other varieties.
This recipe is one of our Better Basics: 10 New Takes on Family Favorites, see the others.