Bistec Encebollado - Chili Pepper Madness

Ingredients

• 1/2 cup olive oil
• 1/2 cup white vinegar
• 3 tablespoons sofrito
• 6 cloves garlic (mashed)
• 2 tablespoon adobo seasoning (or try a combination of adobo and sazon seasoning)
• Salt to taste
• 2 tablespoons vegetable oil
• 2 pounds cube steak (pounded thin, thinly sliced if desired - you can use other steak, see Recipe Notes)
• 2 large onions (sliced (white or yellow onions))
• 1 cup chicken stock
• 2 tablespoons cold butter (optional (to thicken the gravy, if desired))