While the pasta cooks, place basil, pistachios, cheese and garlic in a food processor or mortar and pestle. Process or pound until a coarse paste starts to form.
Add olive oil and lemon and process to desired texture. Check seasoning and adjust to taste.
Once pasta is al dente, drain pasta and return to the pot. Add pesto and mix well.
Serve with extra grated cheese, a side salad and extra protein if desired (see notes above).