Put the pasta on to boil, in lightly salted water.
Once the pasta has gone on, fry the prosciutto, Parma ham or bacon on a high heat until crispy, 2 to 3 minutes. Remove from pan, and drain on kitchen paper.
After the pasta has been boiling 5 minutes, add the peas and beans.
Mix the egg and cream together in a separate bowl.
Once the pasta is cooked, drain. Pour the egg and cream mixture into the pan with the drained pasta, and stir through for a minute for the mixture to cook and thicken. If needed, put back on a gentle heat - be careful, this will only take less than a minute!
Sprinkle with the grated Parmesan and serve.
If you want to make this low fat, substitute creme fraiche for the cream, and sprinkle with fresh chopped chives or mint instead of the Parmesan.