Polpette (Italian Meatballs)

Coarsely chop 2 large onions and place in a food processor fitted with the blade attachment. Add 10 cloves garlic and pulse until finely chopped, scraping down the sides of the bowl as needed.

Heat 1/4 cup olive oil in a large Dutch oven over medium-high heat until shimmering. Add the onions, garlic, 2 teaspoons dried oregano, 1/2 teaspoon of the kosher salt, and 1/4 teaspoon red pepper flakes. Cook, stirring occasionally, until most of the liquid from the onions is evaporated, 10 to 12 minutes. (Reduce the heat if the onions begin to take on any color.)

Reduce the heat to medium and cook until the onions are soft and look shiny, 4 to 5 minutes. Transfer half of the cooked onions and garlic to a large bowl and set aside while you finish the sauce.

Add 2 tablespoons unsalted butter to the pot and stir to combine. Cook until the onions have reduced in volume, are very soft, and begin sticking to the bottom of the pot, 8 to 10 minutes. Add 2 tablespoons tomato paste and stir to combine. Cook until darkened and fragrant, 2 to 3 minutes. Add 2 cans whole tomatoes with their juices, stirring and scraping the bottom of the pot. Add 3/4 cup water to each can and swirl to release tomatoes from the sides of the cans. Add the tomato-water mixture to the pot and stir to combine.

Using an immersion blender, pulse the tomatoes until you reach your desired texture. (Alternatively, use a potato masher or wooden spoon to break up the tomatoes into small pieces.)

Add 1 bay leaf and the remaining 1/4 teaspoon kosher salt to the pot. Bring the sauce up to a boil over medium-high heat. Reduce the heat to low and simmer, stirring occasionally, while you prepare the meatballs.

Tear the inside of about 1/2 loaf Italian bread into small pieces to get 2 cups loosely packed bread pieces and add to a medium bowl. Pour 1 1/2 cups whole milk over the bread.

Prepare the following, adding each to the reserved bowl of onion-garlic mixture you complete it: Pick and coarsely chop the leaves from 1/2 bunch fresh parsley until you have 1/4 cup. Finely grate 2 1/2 ounces Pecorino Romano cheese (about 1/2 cup). Finely grate the zest of 1/2 medium lemon (about 1 1/2 teaspoons).

Add 3 large eggs, 1 tablespoon tomato paste, 2 teaspoons kosher salt, 1 teaspoon fennel seeds, and 1/2 teaspoon black pepper to the onion-garlic mixture. Squeeze as much milk as possible out of the torn bread as you can, then add the bread to the onion-garlic mixture. Discard the milk.

Stir the bread mixture with a wooden spoon or fork until combined. Add 1 pound ground beef and 1 pound ground pork, breaking the meat into smaller pieces with your fingers as you add it to the bowl. Using your hands, gently mix until combined.

Using damp hands to prevent sticking, form the mixture into 25 to 30 golf ball-sized meatballs (a little less than 2 ounces each) and place on a baking sheet or large platter. Refrigerate 1 hour.

Heat 2 teaspoons olive oil in a 12-inch skillet (preferably nonstick) over medium heat until shimmering. Add enough meatballs so that they’re spaced out about 1-inch apart (about 10). Cook until browned on two sides, flipping halfway through, 5 to 6 minutes total. Transfer to a paper towel-lined plate. Repeat cooking the remaining meatballs.

Using tongs, add the meatballs one at a time to the sauce and gently push down on them so that they’re mostly submerged. Cover and simmer until cooked through, 10 to 15 minutes.