Homemade Four Cheese Ravioli

Method

1. Set the whole milk ricotta in a fine sieve over a bowl and drain it in the refrigerator for at least 2 hours or overnight. Wet ricotta turns to liquid in the boiling water and blows the ravioli open.
2. Mound the 00 flour on the counter, make a wide well, and crack in 3 of the large eggs plus the 2 large egg yolks with the olive oil and 1/2 teaspoon of the kosher salt. Beat the eggs with a fork, drawing in flour from the walls, until a shaggy mass forms, then knead 10 minutes until smooth and springy. Wrap and rest 45 minutes.
3. Beat the drained ricotta with the mozzarella cheese, 1/2 cup of the Parmesan cheese, the Pecorino Romano cheese, the ground nutmeg, black pepper, and 3/4 teaspoon of the kosher salt until thick and uniform. Refrigerate until you are ready to fill.
4. Roll the dough through a pasta machine in quarters, taking it down one setting at a time to the second-thinnest, until you can see the shadow of your hand through the sheet. Keep the sheets you are not using covered.
5. Beat the remaining large egg with a splash of water. Pipe or spoon teaspoon-sized mounds of filling along one sheet at 2-inch (5.1 cm) intervals, brush the egg wash around each, lay a second sheet over, and press outward from each mound to expel every air pocket before cutting with a wheel. Trapped air expands and splits the ravioli.
6. Boil the ravioli in well-salted water in batches for 3 to 4 minutes, until they float and the sealed edges are tender. Keep the water at a gentle roll rather than a hard boil.
7. Meanwhile cook the unsalted butter in a wide skillet over medium heat for 4 minutes, until the milk solids turn nut brown and it smells toasted, then add the fresh sage leaves for 30 seconds until crisp.
8. Slide the drained ravioli into the brown butter with a spoonful of pasta water, swirl to coat, and finish with the lemon zest, the remaining 1/2 teaspoon kosher salt, and the remaining 1/4 cup Parmesan.