Pistou sauce is the French version of pesto and is used to spice up Provençal dishes. It is also the basis for the traditional Pistou soup.
Wash and dry the fresh basil. Place it in a mortar.
Add the peeled and coarsely chopped garlic cloves. Add half the olive oil and grated Emmental cheese (optional).
Using a pestle, crush the basil leaves and garlic to form a smooth paste. Then slowly add the remaining oil. Finally, add a pinch of salt.