Wash the sweet potato, peel it, cut it into cubes and boil it in salted water for about 20 minutes. Drain the water and mash the potatoes.
Wash the majoran, sage and rosemary, shake dry and finely chop. Wash tomatoes and cut into small pieces if necessary. Slice or grate the Parmesan.
Knead the mashed sweet potatoes with egg and some flour using a spatula. Gradually work in the remaining flour. Season with salt and nutmeg. Then chill for about 20 minutes.
Shape the gnocchi dough into rolls about 2 cm thick on a floury work surface. Cut the rolls into 1.5 cm long pieces. Shape each piece into a ball and press it onto the surface of the ball with a fork, gently rolling it off.
Then cook the gnocchi in slightly simmering salted water for about 3 minutes.
Melt some butter in a pan and toss in it with a portion (a quarter) of the gnocchi, herbs and tomatoes. Season with salt and pepper. Repeat this with each serving.
Drizzle the gnocchi with olive oil and serve sprinkled with Parmesan.