Gnocchi: Peel and quarter the potatoes and cook them in salted water. Put about 2 of the cooked potatoes with the basil in a blender and puree. Press the rest of the potatoes through a potato press.
Mix the potato and basil mixture with the pressed potatoes, semolina and salt to a smooth dough and let it rest for about 45 minutes. Take some of the dough and form a roll of about 2cm thick and then cut it into pieces about the size of a thumb.
Form the gnocchi into shape and press the typical grooves into them with a fork, place the gnocchi on baking paper and cover them until further use. Finally put the gnocchi in boiling salted water until they float on top.
Tomato sauce: Peel onion, dice finely and fry in some butter until transparent.
Add the cherry tomatoes and herbs, heat, season and finally stir in the sour cream. Garnish with the basil.