In a very large, heavy pot, brown meat in oil. Add onions, continue to cook until translucent.
Add beef broth, red wine, celery, 1 tablespoon each of dried savoury and black pepper, and 2 teaspoon salt. Bring up to almost a boil, reduce heat and simmer – covered – for two hours.
Remove celery from the stew, discard. Add rutabaga, parsnips, carrots, and mushrooms, continue simmering for another hour.
Add potatoes and Brussels sprouts. Cover and simmer for another hour or so.
While the stew simmers, prepare your roux:
In a large heavy pot, combine vegetable oil and butter. Heat over medium until the butter melts, stir in the flour.
Without leaving your stove (Seriously!), stir the mixture constantly over medium heat until it gets quite dark – I like to get it to a reddish brown colour. It’ll take time, but it’s worth it – this great flavour to the stew … just don’t burn it!
Stir a ladle worth of stew stock into the roux – it’ll boil up and steam, don’t worry. Whisk it till smooth, then add another ladle worth of stew liquid. Continue until you have a decent amount of smooth gravy.
Add the gravy into the stew, stirring well to fully distribute. Stir in fresh parsley, season with salt, pepper, and additional savoury to taste.