In a shallow dish, combine vinegar, 1/4 cup EVOO, garlic, marjoram or oregano, cilantro and cumin.
Pat steaks dry, season with salt and pepper and give them a turn in the marinade. Let marinate 4 hours in the fridge.
Heat a skillet over medium heat with 2 tablespoons EVOO. Add onions, season with salt and pepper and cook until tender, about 20 minutes. Deglaze the pan with the beer or chicken stock. As onions cook, take the meat out of the fridge to bring it back up to room temperature before cooking.