Cube beef into 1 inch cubes and place in a large bowl. Sprinkle beef with 2 tablespoons tapioca flour, salt, and garlic salt; toss the cubes in the flour mixture to coat.

In a large dutch oven over medium high heat, warm 1 tablespoon of the oil and add half of the floured beef cubes, then brown the beef on all sides. Transfer the beef to the slow cooker. Add another tablespoon of oil to dutch oven and brown the rest of the meat on all sides.

Add the garlic to the dutch oven and cook for 30 seconds to 1 minute or until garlic becomes fragrant. Add to the slow cooker. Add the remaining tablespoon of oil to the pot and cook the onion and celery for 4-5 minutes or until softened, then add to the slow cooker with the beef. Add 1 cup of broth to the Dutch oven and bring to a boil, scraping the bits from the bottom of the pot. Whisk the 2 remaining tablespoons of flour into 2 tablespoons of the beef broth, then mix into the rest of the liquid and add to the slow cooker with the vegetables, bay leaves, and thyme. Cook on high for 3 hours or low for 6 hours. Remove the bay leaves and serve.