Place beef into a bowl; cover with vinegar and salt.
Heat oil in a large skillet over medium-high heat; cook and stir onion until softened, 3 to 5 minutes. Add meat to the onions; cook and stir until onions are soft and meat has begun to brown, about 5 minutes.
Mix corn, peas, and mushrooms into the skillet; cook and stir until flavors combine, about 10 minutes. Stir in tomato sauce and cream. Cook and stir until meat is cooked through and a salmon pink color, about 3 minutes. Season with salt.