In a large saucepan over medium-high heat, combine the onions, celery, carrots, and potatoes, if using, as well as the cooking fat. Cook for 3 to 5 minutes, stirring constantly.
1 cup onion, 1 cup celery, 3 carrots, 2 potatoes, 2 tablespoon paleo cooking fat
Add the beef to the saucepan, followed by the tomatoes, beef stock, rosemary, and thyme. Season to taste with salt and pepper.
1 lb stewing beef, 4 cups beef stock, 1 28 oz can diced tomatoes, ½ teaspoon fresh rosemary, ½ teaspoon fresh thyme, Sea salt and freshly ground black pepper to taste
Cover the saucepan and cook for about one hour, allowing the stew to simmer. Stir a few times during the cooking process.
Remove the lid and cook uncovered for about 45 minutes. If the mixture is too thick at the end of the cooking process, you can add a little bit of water or stock.