Wash and halve the tomatoes. Line a baking tray with baking paper. Spread tomatoes on it and season with salt. Cook in the preheated oven (electric cooker: 125 °C/ circulating air: 100 °C/ gas: see manufacturer) for about 45 minutes.
For the spaetzle, mix flour and 2 teaspoons salt in a bowl. Wash the basil, dab dry. Pluck the leaves and put them into a tall mixing bowl, except for a little garnish. Add eggs and puree with 100 ml water. Gradually stir the mixture into the flour. Beat with a wooden spoon until the dough starts to bubble. Put the dough in portions into a spaetzle press and cook in boiling salted water for 3-4 minutes. Lift out with a skimmer and drain on a sieve. Keep warm.
Wash, drain and clean the chanterelles briefly but thoroughly. Peel and chop the onions. Heat the oil in a large pan. Fry the chanterelles thoroughly. Add the onions and fry with them. Add bresso and cream, season with salt and pepper. Simmer for 5 minutes, season again. Carefully mix the sauce with the noodles and the tomatoes. Serve garnished with set aside basil.