Heat the bacon grease over medium high heat in a large dutch oven. Add the sliced onions, carrot, celery, mushrooms, and a pinch of salt. Cook over medium-high heat until onions begin to brown, stirring often, about 10 minutes. Add the garlic and cook until fragrant, about one minute. Add tomato paste, stirring to distribute evenly. Cook another 2 minutes then add the wine, scraping to ensure nothing is stuck to the bottom of the pot. Add a cup of chicken stock, fish sauce, gelatin, thyme, bay leaves, and Worcestershire sauce. Bring to a boil then add the beef and salt. The beef should be completely submerged. Add more stock as needed.