Step 1

Bring a large pot of well-salted water to a boil. Meanwhile, do some prep. First, chop ¾ cup walnuts so they’re roughly the size of peas.

Step 2

Smash 5 garlic cloves, peel, and discard skins. (You don’t want the cloves to be obliterated, but smashed enough create plenty of surface area.)

Step 3

Cut ½ cup (1 stick) unsalted butter into 8 pieces and transfer to a large skillet. Heat skillet over medium-low and cook butter, swirling often, until just melted, 2–3 minutes.

Step 4

Add walnuts and garlic and continue to cook, stirring often with a heatproof spatula, until nuts and garlic are light golden brown and butter solids are browned as well, 3–4 minutes longer. It will get very foamy and hard to see the bottom of the skillet, so use spatula to drag through butter—you should leave a trail of little brown specks in your wake (a.k.a. toasty, delicious milk solids).

Step 5

Add 16 sage leaves and cook (still over medium-low heat), stirring constantly, until sage crackles and is dark green and crisp, about 1 minute longer. Remove skillet from heat. Hot tip: If you think things are getting too dark, add a splash or two of pasta cooking liquid to the hot pan; this will halt the browning process. Season with 1½ tsp. salt and ½ tsp. pepper.

Step 6

Cook 1 lb. store-bought cheese tortellini (or other stuffed pasta) in boiling salted water and set a timer according to package directions, but start checking doneness a minute early. Fresh pasta packages are often a little generous with their cook times, so it pays to check sooner rather than later—you don't want falling-apart pasta! Stir pasta once or twice as it cooks to ensure it cooks evenly.

Step 7

When pasta is cooked, drain and transfer to butter sauce. Return skillet to medium heat and cook, stirring and tossing, until pasta is well coated in sauce, about 30 seconds. Remove from heat and stir in 2 tsp. apple cider vinegar. Taste sauce and add more salt if needed.

Step 8

Divide tortellini among plates. Sprinkle with 2 oz. Parmesan and a few good cranks of pepper.