For the mussels in the baking paper packet, first preheat the oven to 160 °C.
Wash the mussels well, clean them and separate them. Portion the mussels on the baking paper with each orange and lemon slice, parsley, a ginger slice, bay leaf, a thyme sprig and unpeeled garlic cloves and wrap.
Pinch the ends tightly together. Steam the mussels in the baking paper packets in the preheated oven on the middle rack for 15-20 minutes.
For the marinade, sauté the onion and garlic in the olive oil in a saucepan until translucent and pour in the clear vegetable soup. Add parsley, diced tomatoes and thyme, season with salt and cayenne pepper.
At the end of the cooking time, remove the mussel packets from the oven, place them on preheated plates and open the baking paper. Separate the mussels that have not opened.
Drizzle the tomato marinade and olive oil over them and serve the mussels in the baking paper packet.