6 ounce sliced pancetta or bacon, cut into 1/4”-wide strips
1/2 cup whipping cream
2 garlic cloves, finely chopped
1/4 teaspoon dried crushed red pepper
3 tablespoons olive oil
1 1/2 pound zucchini, thinly sliced
1 pound bucatini or spaghetti
3 large eggs
1 cup freshly grated Parmagiano-Regiano
Cook pancetta in a medium skillet over medium heat until brown, stirring often, about 8 minutes. Using slotted spoon, transfer pancetta to paper towel; drain off all but 2 tablespoons dripping from skillet. Add cream, half of garlic, and crushed red peppers to drippings in skillet; bring to a boil. Set cream mixture aside.
Heat oil in a heavy, large skillet over medium-high heat. Add remaining garlic and zucchini; sauté until tender, stirring occasionally, about 10 minutes. Transfer to a large plate. Season with salt and pepper. (Pancetta, cream mixture, and zucchini can be made 2 hours ahead. Let stand at room temperature.)
Cook pasta in a large pot of boiling, salted water until just tender but still firm to bite. Drain well. Return pasta to pot.
Meanwhile, place eggs, in their shells, in a small bowl. Add enough hot water to cover. Let stand 5 minutes. Crack eggs into a large bowl and whisk to blend. Bring cream mixture to a boil in skillet. Gradually whisk hot cream mixture into eggs. Mix in 1/2 cup cheese.
Add pasta to sauce and toss over medium heat until sauce coats pasta (do not boil). Add pancetta and zucchini; toss to heat through. Season with salt and pepper. Serve, passing remaining cheese.