Peel, wash onions and carrots. Dice the onion. Grate carrots on a coarse grater.
Preheat a frying pan. Pour in vegetable oil. Place the onions and carrots. Simmer vegetables, stirring occasionally, over medium heat for 3-4 minutes. Cool down.
Place prepared vegetables in a bowl. Add mustard, sour cream, sugar, salt, pepper, barbecue spices, apple cider vinegar. Mix well. The kebab marinade is ready.
Wash the meat, dry it, cut it into portions. Put the prepared meat in the marinade, mix well. Marinate meat for 3-4 hours.
Fry the kebab in any way (on the grill, in a frying pan, in the oven, in an electric BBQ grill), sprinkling the meat lightly with lemon juice before cooking. Serve with fresh vegetables.