Combine the soy sauce, white wine, sherry in a bowl with Maizena, add the garlic and the meat, mix well and let steep for about 30 minutes.
Heat half of the oil in a pan. Sauté the peppers, peppers and onions well, stirring again and again for about 5 minutes. Take everything out of the pan and set aside.
Remove the meat from the marinade, drain well, but save the marinade.
Heat some more oil very hot, fry the meat vigorously in it for just under 2 minutes, deglaze with the marinade, add the tomato puree and add the steamed peppers. Let simmer for 3-4 minutes, season to taste with salt and pepper.