Step 1

Heat oil in a large skillet over medium. Cook guanciale, tossing often, until browned and crisp, 6–8 minutes. Add shallots and garlic and cook, stirring occasionally, until softened, about 5 minutes. Add pepper and cook, stirring often, just until fragrant, about 1 minute.

Step 2

Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain, reserving 1 1/2 cups pasta cooking liquid.

Step 3

Add pasta to skillet along with 1/2 cup pasta cooking liquid and 1 oz. Parmesan and toss to coat. Remove skillet from heat and add egg yolks. Toss again, adding more pasta cooking liquid as needed, until a smooth glossy sauce coats pasta. Add grated lemon zest, lemon juice, and another 1 oz. Parmesan. Toss to coat, adding more pasta cooking liquid if needed to loosen sauce.

Step 4

Divide pasta among bowls; top with sliced lemon zest and more Parmesan.