Cook the tortellini according to the package instructions. Meanwhile, prepare onions and courgette. Melt butter in frying pan. Saute the onions till soft, about 3 minutes. Add courgette and marjoram and saute 5 minutes, stirring occasionally.
Grate the cheese into a bowl. Stir in the creme fraiche, pepper, and garlic. Add the cheese mixture to the courgette. Cook over low heat, stirring occasionally, about 5 minutes, till heated through.
Drain the tortellini and add to courgette mixture. Divide between two plates. Lekker with tomato salad.