In a large stockpot melt butter and cook onions until translucent. Add the ground beef and cook until browned, seasoning with salt, black pepper, garlic powder, and cayenne pepper. Add Remaining ingredients except flour and bring to simmer and cover for 1 hour, stirring occasionally. Using a ladle, skim off most of the beef fat, reserving 3 tablespoons of fat.
In a small bowl mix 3 tablespoons reserved fat with three tablespoons flour until smooth. Add flour mixture to stew and stir. Taste and adjust for seasoning.