Sprinkle both sides of roast generously with salt and pepper.
Dredge in flour.
Brown meat on both sides in oil over medium heat.
Place browned meat in slow cooker.
Add beef broth, onions and mushrooms.
Cook about 3-4 hours on high.
Add potatoes and carrots. (Add more if you need more for your family).
Continue cooking another hour and a half to two hours until carrots and potatoes are fork tender.
Remove carrots, potatoes, onions and mushroom to separate serving bowls. Keep warm.
Remove beef roast to platter and slice or chunk down.
Pour remaining beef broth mixture from crockpot into a large saucepan.
Heat over medium heat until mixture boils.
Mix about one-fourth to one-third cup of gluten free flour with about the same amount of water. (Or use regular flour).
Whisk to combine.
Add flour mixture about a tablespoon at a time to crockpot and keep whisking until all the flour mixture is incorporated.
If the gravy is not as thick as you like, repeat adding more flour/water mixture.
Add Kitchen Bouquet seasoning and continue whisking until mixture thickens and boils.
Season with more salt and pepper, if desired.
Stir to combine and serve.