Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). 1 teaspoon cumin, 1 teaspoon sumac (If you don't have the fruity and sour spice powder in your kitchen cupboard, you can also season with 1 teaspoon lemon juice.
However, sumac does not have such an intense acidity as lemon juice) and mix 1 level tablespoon of salt. Peel onions and cut into slices. Peel and wash root vegetables, cut them in half lengthwise depending on their size and cut into thin slices.
Mix the vegetables with 4 tablespoons of oil and the prepared spice mix. Spread on a baking tray and roast in a hot oven for about 30 minutes.
For the vinaigrette, whisk vinegar, salt, pepper, mustard and honey. Add 6 tablespoons of oil. Roast the pumpkin seeds and sesame seeds in a pan for about 2 minutes. Select the salad, wash and drain well.
Drain the mozzarella. Take the vegetables out of the oven and let them cool down. Mix carefully with mozzarella, salad and vinaigrette. Sprinkle with the seeds and serve.