Step 1

Place 4 cups all-purpose or ‘00’ flour and 1 teaspoon kosher salt in the bowl of a stand mixer fitted with the dough hook attachment. (If you’d like to make the dough by hand, follow the directions here.) Mix on low speed for a few seconds to combine.

Step 2

Add 4 large eggs, 4 large egg yolks, and 2 tablespoons olive oil. Mix on medium-low speed until the dough starts to form a ball and pull away from the sides of the bowl, scraping down the sides of the bowl and the dough from the dough hook once or twice, about 5 minutes. If after 1 to 2 minutes your dough still looks crumbly and dry, gradually add up to 4 tablespoons of cold water, 1 tablespoon at a time, until it comes together.

Step 3

Dust a work surface lightly with all-purpose or ‘00’ flour. Scrape the dough onto the flour and knead until the dough is smoother, less sticky, and more elastic, 5 minutes. Wrap the dough tightly in plastic wrap and refrigerate for at least 20 minutes and up to 24 hours. If the dough is very cold, let it sit at room temperature for 20 minutes before rolling it out.

Step 4

Drain and cut 4 ounces fresh mozzarella cheese into small cubes; add to a food processor fitted with the blade attachment. Grate 1 ounce Pecorino Romano cheese and 1/2 ounce Parmesan cheese on the small holes of a box grater (1/4 cup each), and add to the food processor.

Step 5

Add 1 container ricotta cheese, 1/2 teaspoon kosher salt, and 1/8 teaspoon freshly grated nutmeg if desired. Process until smooth, scraping down the sides as needed, about 1 minute.

Step 6

Transfer the filling to a piping bag fitted with a wide, round tip. Alternatively, transfer the filling into a large resealable plastic bag and push into one bottom corner; cut the corner of the bag when you’re ready to fill the ravioli. Refrigerate the filling while you roll out the pasta dough.

Step 7

Unwrap the dough and cut into 3 pieces (about 12 ounces each). Rewrap 2 pieces of the dough in the plastic wrap to keep them from drying out.

Step 8

Roll out each piece of dough: Set a pasta roller to the thickest setting. Flatten the piece of dough into a thick disk between your hands, dusting with semolina flour if it feels sticky. Feed it through the pasta roller. Repeat once or twice. Fold this piece of dough into thirds, like a letter, and press it between your hands again.

Step 9

With the pasta roller still on the widest setting, feed the pasta crosswise (folded-side in first) between the rollers. Feed it through once or twice more, until smooth. If desired, repeat this folding step. This helps to strengthen the gluten in the flour, giving it a chewier texture when cooked.

Step 10

Begin changing the settings on the roller to roll the pasta thinner and thinner. Roll the pasta 2 or 3 times at each setting (no need to fold anymore), and don't skip settings (the pasta tends to snag and warp if you do). If the pasta gets too long to be manageable, lay it on a cutting board and cut it in half crosswise before you continue rolling.

Step 11

Roll the pasta as thin as you can get it, then sprinkle generously with semolina and lay flat on a parchment paper-lined baking sheet with sheets of parchment in between each pasta sheet. Repeat until all the dough is rolled out.

Step 12

Line a second baking sheet with parchment paper and sprinkle with semolina flour. Sprinkle a work surface with semolina flour and arrange a pasta sheet on top with a long side closer to you.

Step 13

If the pasta sheet is at least 4 inches wide from top to bottom, pipe 1 -teaspoon portions of the filling onto the bottom half of the pasta sheet about 1-inch apart. Gently brush a little water on the top half of the pasta sheet, then gently fold the top half over the bottom half.

Step 14

If the pasta sheet is less than 4 inches wide, pipe 1 -teaspoon portions of the filling down the center of the sheet about 1-inch apart. Gently brush a little water around the border of the sheet. Gently top with a second sheet of pasta.

Step 15

Use your fingers to press out any air bubbles and seal the dough all the way around each portion of filling. Using a pasta cutter or sharp knife, cut around each portion of filling to form individual raviolo. Don’t worry if they are not perfect — they will still taste great.

Step 16

Transfer the ravioli to the baking sheet and repeat filling all the pasta sheets. You can cut up any pasta scraps and cook them up for a snack. If you don’t plan to cook the ravioli right away, refrigerate uncovered for up to 4 hours. (See Recipe Notes for freezing instructions.)

Step 17

Bring a large pot of heavily salted water to a boil. Working in batches of about 20 ravioli, add the ravioli and cook until the pasta is cooked through and al dente, 4 to 5 minutes. Remove the ravioli with a large slotted spoon or spider and toss with desired sauce.