Serves 4 as a main course or 6 to 8 as a side dish

If you’re in a hurry or prefer to sprinkle the dish with crumbled common crackers (saltines aren’t bad either), you can skip the bread crumb step.

Serves 4

The pasta and sauce cook in just about the same amount of time. If you like the fruitiness of extra-virgin olive oil, toss 1 tablespoon into the sauced pasta before serving.

Serves 4 to 6

We prefer the flavor and texture of chunky peanut butter in the sauce; in particular, we like conventional chunky peanut butter because it tends to be sweeter than natural or old-fashioned versions.

Serves 8 to 10 as a side dish

This salad is best served the day it is made; if it’s been refrigerated, bring it to room temperature before serving. The pesto can be made a day ahead—just cook the garlic cloves in a small saucepan of boiling water for 1 minute. Garnish with additional shaved or grated Parmesan.

Serves 4

Do not substitute no-boil lasagna noodles for the traditional, curly-edged lasagna noodles here. Meatloaf mix is a combination of ground beef, pork, and veal, sold pre-packaged in many supermarkets. If it’s unavailable, use 1/2 pound each ground pork and 85 percent ground beef. We recommend using either whole milk or part-skim ricotta here, but do not use fat-free ricotta, which has a very dry texture and bland flavor.

Serves 4 to 6 as a first course

Fresh pasta is the best choice for this dish; supermarkets sell 9-ounce containers of fresh pasta in the refrigerator section (see related article for tasting results). When boiling the pasta, undercook it slightly (even shy of al dente) because the pasta cooks an additional minute or two in the sauce. Note that Fettuccine Alfredo must be served immediately; it does not hold or reheat well.

Makes 4 cups

This recipe makes enough to sauce more than a pound of pasta; leftovers can be refrigerated or frozen. Because canned tomatoes vary in acidity and saltiness, it’s best to add salt, pepper, and sugar to taste just before serving. If you prefer a chunkier sauce, give it just three or four pulses in the food processor in step 4.

Serves 4 to 6

This dish will be very warm, not hot. The success of this recipe depends on high-quality ingredients, including ripe, in-season tomatoes and a fruity olive oil (the test kitchen prefers Columela Extra-Virgin). Don’t skip the step of freezing the mozzarella, as freezing prevents it from turning chewy when it comes in contact with the hot pasta. If handmade buffalo- or cow’s-milk mozzarella is available (it’s commonly found in gourmet and cheese shops packed in water), we highly recommend using it, but skip the step of freezing and add it to the tomatoes while marinating. Additional lemon juice or up to 1 teaspoon sugar can be added at the end to taste, depending on the ripeness of the tomatoes.

Serves 4 to 6

High-quality ingredients are essential in this dish, most importantly, imported Pecorino Romano—not the bland domestic cheese labeled “Romano.” Use the small holes on a box grater to grate the cheese finely and the large holes to grate it coarsely. Alternatively, a food processor may be used to grate it finely: Cut the Pecorino into 2-inch pieces and process until finely ground, about 45 seconds. For a slightly less rich dish, substitute half-and-half for the heavy cream. Do not adjust the amount of water for cooking the pasta. Stir the pasta frequently while cooking so that it doesn’t stick to the pot. Letting the dish rest briefly before serving allows the flavors to develop and the sauce to thicken.

WHY THIS RECIPE WORKS:
With just three main ingredients (cheese, pepper, and pasta), this Roman dish makes a delicious and quick pantry supper. But in versions we tried, the creamy sauce quickly turns into clumps of solidified cheese. We wanted a sauce that was intensely cheesy but also creamy and smooth.

Our science editor explained why the cheese clumps in this dish. Cheese consists mainly of three basic substances: fat, protein, and water. When a hard cheese like Pecorino, our cheese of choice, is heated, its fat begins to melt and its proteins soften. The fat acts as a sort of glue, fusing the proteins together. In order to coat the cheese and prevent the proteins from sticking together, we needed to introduce a starch into the mix.

It occurred to us that as pasta cooks, it releases starch into the water. We reduced the amount of water to concentrate the starch and whisked some of the cooking liquid into the cheese. This helped to a point, but we found we also needed an emulsifier—something to bind together the sauce. We turned to cream. By switching the butter for cream, we created a light, perfectly smooth sauce that had all the cheese flavor we wanted. Even after sitting on a table for a full five minutes, there wasn’t a clump in sight.

Serves 4