• Chop the prosciutto with a knife into small cubes.
• In a nonstick pan, cook just 50 g of the chopped prosciutto, without oil or butter, for a few minutes or until browned. It has to be crunchy. Turn off the heat and set aside.
• In the same pan, melt the butter in the olive oil, over low heat on a small burner, adding the lemon zest as well. If you made lemon butter, use it.
• When the butter is completely melted, add the ham and cook for one minute, keeping the heat low and using a small burner. Be careful not to overcook the ham, or it will become too salty.
• Cook the tagliatelle in a large pot of boiling salted water for 3–4 minutes after the water returns to a boil. Set aside a little of the cooking water just before draining the pasta.
• Drain the tagliatelle and place them to the pan. Sauté over medium heat on a small burner, stirring to combine with the sauce and gradually adding the reserved cooking water, a little at a time, until the sauce is creamy and not watery. Add more butter if needed.
• Serve immediately, adding a bit of crispy prosciutto to each plate and serving the grated Parmigiano Reggiano on the side.

Tips

• If you want to use lemon juice, add just a little to keep the sauce from becoming too sour.
• To enhance the lemon flavor, flavor the butter with lemon zest. Here’s how: mix the softened butter (taken out of the refrigerator) with a teaspoon of grated lemon zest. Return the butter to the refrigerator so it hardens and retains the zest’s aroma. Use as needed. You can prepare it a few days in advance. Don't add too much lemon zest when flavoring the butter, or the flavor will be too strong.