Crush the walnuts in a mortar and toast them in a frying pan. You can do this without oil, as the walnuts release their own oil.
25 g walnuts
Meanwhile, press or grate the garlic. Grate the cheese (if using).
25 g Parmesan, 1 clove garlic
Combine all the ingredients in a small food processor and blend until you have a slightly coarse pesto.
25 g arugula, 50 ml olive oil, 0.5 lemon, 1 pinch salt
Reserve a little cheese or 1 tablespoon of nutritional yeast and a little olive oil so you can adjust the consistency after blending if needed.
Notes
The quantity for 4 servings is intended as an appetizer spread. If you use the pesto as a pasta sauce or in a salad, it makes 1 to 2 servings.Cow's milk-free version: use 25 g of grated pecorino instead of Parmesan.Dairy-free, paleo and vegan version: use 3 tablespoons of nutritional yeast flakes instead of cheese.Equipment: (Small) food processor or immersion blender, small PFAS-free frying pan, garlic press, (four-sided) box grater.