Melt butter in a skillet over medium heat, add onion, garlic and mushrooms. Saute for about 10 minutes. Remove from pan, set aside.
Dredge beef stew meat in flour/salt/pepper mixture.
Add oil to skillet, brown meat.
Add beef stock, Worcestershire sauce, ketchup and kitchen bouquet to skillet. Stir to combine, gravy will thicken as it heats. Cover and simmer for 30 minutes or so. (note: the longer you simmer the more tender your meat will be.) Add mushrooms back in. Simmer for 10 minutes or so more. If you prefer a thicker gravy, add a little cornstarch/water mixture to thicken even more.