Clean, wash and finely chop the spring onions. Sort out the rocket, remove coarse stems, rinse and spin dry. Finely chop half of it, set the rest aside.
Cook the penne al dente in plenty of salted water. Heat the oil in a saucepan and sauté the spring onions while stirring. Sweat the chopped rocket leaves briefly. Pour in white wine and broth and let everything boil down over low heat for about 5 minutes.
In the meantime, wash the cocktail tomatoes and cut them in half. Mix the crème fraiche into the sauce, season with salt, pepper and lemon juice. Drain the pasta, drain well and mix with the sauce.
Line four plates with a portion of the whole arugula leaves that were set aside. Place the pasta with the sauce on top and garnish with the tomato halves and the remaining rocket.