Roast the hazelnut kernels in a pan without fat, take them out and let them cool down. Wash the parsley, dab dry well and pluck the leaves from the stalks. Peel the garlic and cut the Parmesan roughly into pieces. Put parsley, nuts, garlic and parmesan into the blender jug of a food processor and chop everything finely. Then gradually add 200 to 250 ml olive oil and mix in. Wash the chilli pepper, cut into fine rings and remove the seeds.
Wash lemon hot, dab dry and finely grate half of the peel. Stir the lemon peel and chili into the finished pesto and season with salt and possibly a little pepper. Pour pesto into 4 glasses (125-150 ml each). Pour some olive oil on each pesto (pesto covered with oil keeps longer) and close well. Stored in a cool and dark place it will keep for at least 1 week.