Clean, wash and cut the cauliflower into florets. Blanch the cauliflower florets in boiling salted water for 2-4 minutes. Drain and leave to drain well in a sieve. Clean, halve or quarter the mushrooms.
Clean, wash and cut the spring onions into pieces of about 4 cm. Wash the thyme, shake dry and remove the leaves.
Place the cauliflower, mushrooms, spring onions, thyme and 3 tbsp. olive oil in a bowl and mix well. Season with salt and pepper. Spread everything on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see
manufacturer) cook for 20-25 minutes.
In the meantime, mix vinegar and mustard for the vinaigrette. Season with salt and pepper. Stir in 2 tablespoons of olive oil drop by drop. Wash the salmon, dab dry and cut into four slices. Wash lemon, grate dry, grate peel thinly.
Halve the lemon, squeeze half of it. Sprinkle fish slices with it (use the remaining half of the lemon for other purposes). Season with salt and pepper. Heat 1 tablespoon of olive oil in a large, coated frying pan.
Fish in it from both sides 3-4 minutes sear. Remove and sprinkle with lemon juice. For the dip, stir the quark and milk until smooth. Stir lemon zest into the quark. Season to taste with salt and pepper.
Remove the vegetables from the oven and mix with the vinaigrette. Season again with salt and pepper if necessary. Crumble the feta and mix into the vegetable salad. Arrange the salad on plates and arrange 1 salmon strand on each plate.
Garnish with thyme as desired.