Roast the pine nuts in a pan without fat, take them out and let them cool down. Grate cheese. Cut off radish leaves, wash well and shake dry. Puree half the leaves with pine nuts, parmesan, horseradish and 120-150 ml oil. Season to taste with salt and pepper.
Wash the radishes and cut them into slices. Peel and chop onion and garlic. Dice baguette finely.
Cook the pasta in 3-4 l boiling salted water (1 teaspoon salt per litre) according to the instructions on the packet. Fry onion, garlic and bread in 4 tbsp. hot oil. Add radishes and fry for about 3 minutes. Season with salt, pepper, 1 pinch of sugar and vinegar. Drain the noodles. Add the rest of the radish leaves to the pan and mix everything. Serve with pesto.
The great thing about this recipe is that you use the radishes together with their greens. If pesto is left over, simply put it in a screw glass covered with 2 tablespoons of oil. This way it will keep for 1-2 weeks in the refrigerator.