Cook the pasta in salted water until al dente. Peel half the vegetable onion and cut into fine strips. Dice the bacon and peel and finely chop the garlic.
Heat the olive oil in a pan. Sweat the onion strips in it while stirring. Add the bacon and garlic and fry everything for 3 - 4 minutes until crispy. Add the peas and mascarpone to the pan with 3 tablespoons of the pasta water and cook for 1 minute.
Season to taste with pepper, possibly salt and lemon juice.
Drain the pasta, drain, mix with the sauce and serve garnished with basil.