Sauce: very finely chop the onion, whisk the mustard and vinegar, gradually, without stopping whipping, pour in the olive oil. Add salt and pepper. I whipped everything up in a blender. * The sauce was too rich for me, and I added sour cream 4 tbsp. (the Sauce turned out a lot, left it for tomorrow, then pour the salted casserole, drive into the cutlets, pour the vegetable salad.)