Step 1

Bring a large pot of lightly salted water to a boil over high heat. Meanwhile, set a large, high-walled pan over medium-high heat and add lardons. Cook until browned on all sides, about 4 minutes. Use a slotted spoon to transfer lardons to a plate, reserving drippings in pan.

Step 2

In a medium heatproof bowl, beat egg yolks with cheeses and 1 tablespoon coarsely ground black pepper until mixture is thick as glue and uniform. Set aside.

Step 3

Add spaghetti to boiling water and cook 3 minutes less than box specifies. Once noodles are halfway cooked, transfer 3 cups hot pasta water to pan with pork drippings and bring to a boil, scraping up browned bits from pan.

Step 4

Once pasta is 3 minutes shy of al dente, use tongs to transfer it from pot to pan with pork drippings. (Keep water remaining in pot at a boil.) Continue cooking pasta in pan with pork drippings until just al dente, 2-3 minutes.

Step 5

Transfer spaghetti to bowl with egg-cheese mixture and toss, adding splashes of water from pan with pork drippings as needed, until sauce cloaks noodles and looks glossy. Toss in lardons and remaining ½ teaspoon pepper. Add more pepper, salt, cheese or pasta water as needed. Serve immediately.