How to Make It
Preheat the oven to 400°. In a colander set in the sink, combine the sweet potatoes, yellow onion and 3/4 teaspoon of salt. Let drain for 15 minutes, then squeeze out the excess liquid. Transfer the mixture to a bowl. Add the flour and a pinch each of pepper and nutmeg; toss well. Press the mixture into a generously oiled 10-inch pie plate, pushing it up the side and onto the rim to form a crust; brush lightly with oil. Bake the crust for about 25 minutes, or until slightly crisp; cover the rim with foil if it browns too quickly.
Meanwhile, in a medium skillet, heat 1 tablespoon of the olive oil. Add the red onion and garlic and cook over moderate heat until softened but not browned, about 3 minutes. Add the escarole and cook, stirring occasionally, until wilted, about 3 minutes. Transfer the escarole to a colander set in the sink and press out as much liquid as possible; let cool slightly.
In a medium bowl, beat the eggs with 1 cup of the provolone cheese and the milk and oregano. Add the wilted escarole and season with salt and pepper. Pour the mixture into the sweet potato crust and sprinkle the remaining cheese on top.
Reduce the oven temperature to 375°. Bake the torta for about 45 minutes, or until the center is set; cover it loosely with foil if it browns too quickly. Let stand for 5 minutes before serving.
Sliced ham and thick slices of bread spread with apple butter.