Finely grate the parmesan. Peel garlic and chop very finely. Wash and dry the lemon and grate the peel finely. Squeeze the lemon. Wash parsley, shake dry and chop coarsely.
Cook the spaghetti in 3-4 l boiling salted water (1 teaspoon salt per litre) according to the package instructions.
In the meantime, tear the ham into pieces. Fry them crisply in a pan without fat and take them out. Heat the oil in the pan slightly. Sauté the garlic and lemon peel in it. Add lemon juice and bring to the boil.
Season with pepper and 1 pinch of sugar.
Remove 4-5 tablespoons of pasta water and add to the lemon oil. Drain the pasta and pour it back into the pot. Mix with lemon oil and parsley. Flavour again. Sprinkle with ham chips and parmesan.