For a very good, basic tart filling that makes a perfect bed for any vegetable, whisk one and a half cups of ricotta, a quarter cup of good olive oil, two tablespoons cream, a half teaspoon kosher salt, two egg yolks, and a pinch of chopped fresh thyme or rosemary. This makes a very rich, salty custard that if there are no vegetables is a gratifying filling on its own.
