15 ounces whole-milk ricotta cheese
10 ounces frozen chopped spinach, thawed and squeezed dry
4 ounces thinly sliced prosciutto, chopped
2 large egg yolks
3/4 teaspoon salt
1/2 teaspoon freshly ground black pepper
48 square wonton wrappers
1/2 cup (1 stick) butter
1 teaspoons dried sage
Freshly grated Pecorino cheese
Whisk the ricotta, spinach, prosciutto, egg yolks, salt and pepper in a medium bowl to blend.*
Place 1 tablespoon of the ricotta filling in the center of a wonton wrapped. Brush the edge of the wrapper lightly with water. Fold the wrapper in half, point to point, enclosing the filling completely and forming a triangle. Pinch the edges to seal. Repeat with the remaining filling and wrappers. (Ravioli can be prepared up to 2 hours ahead; just cover and chill.)
Bring a large pot of salted water to a boil. Working in batches, cook the ravioli gently until just tender, stirring occasionally, about 4 minutes per batch. Transfer the ravioli to a large, shallow bowl.
Melt the butter in a small, heavy skillet over medium heat and cook until slightly browned and aromatic. Add the sage and stir for 1 minutes. Season to taste with salt and pepper. Pour the sage butter over the ravioli and toss gently to coat. Sprinkle with the Pecorino cheese and serve.
*To simplify this recipe, omit spinach and prosciutto. This is also an easy recipe to cut in half for fewer servings.