We prepare the sauce. Mix the mustard and olive oil. Add yogurt, black pepper, red pepper, and mix. Add salt. I have salt and seasonings, mix.
Cut the ham into strips.
Cucumber is also cut into strips, put on the ham.
Cut the tomatoes into quarters, put them on the cucumber.
Cut the onion into feathers, put it on the tomatoes.
Season the vegetables with the sauce.
Top with the watercress.
Place the mushrooms on the edges of the salad bowl. I have canned mushrooms, I pre-marinated them, left them in the refrigerator overnight. Marinade for 1/2 liter of boiled water-1/2 tbsp salt+1 tsp vinegar (5-6%)+1/4 tsp sugar