Bring a large pot of water to a rolling boil and salt it heavily. Add rigatoni pasta and cook until al dente. Reserve at least 1/2 cup of the pasta water. Drain cooked pasta and set aside.
In a small bowl, whisk together 3 egg yolks, 1/2 cup grated Manchego, and 1/8 tsp smoked paprika. Add a few cracks of black pepper and mix until well combined. Slowly whisk in a small amount of the hot pasta water, until the sauce becomes loose and glossy.
In a pot, add 3-4 slices of jamon iberico and set over a low-medium heat. Cook on both sides until crispy and the fat renders out. Remove the crispy slices and set aside. Add the drained pasta to the pot and stir to combine with the rendered fat.
Off the heat, or with it on the lowest setting, slowly pour in the egg-manchego sauce. Stir immediately until the pasta is fully coated. If the sauce is too thin, gently raise the heat while stirring continuously until it thickens slightly. If it gets too thick, add more pasta water. Optionally stir in more grated Manchego. Taste and add salt and more black pepper as needed.
Serve warm and top with the crispy jamon slices, more grated Manchego, and a small squeeze of lemon juice.