Dice onions. Peel carrots and slice into coin shape pieces.
Pour olive oil into a large stew pot over a medium flame.
Add the diced beef and cook about 5 minutes, making sure all the sides of the beef are brown.
Add diced onions and cook for about 3 minutes until they begin to sweat.
Sprinkle the brown sugar over the beef and onions and cook until caramelise a bit.
Add the beer, thyme, bay leaves, tomato paste, garlic, parsley and carrots. Reduce the flame, cover the pot, and let cook for about 3 hours. Let the stew cook slowly. Do not stir frequently.
After 2 hours add the mustard and stir. Check the liquid and add some water if needed.
After 3 hour check the meat and if it is tender, thicken the sauce with brown roux. Do not make the sauce too thick.
Season with salt and pepper.
Serve with mushed potatoes, boiled potatoes, french fries or rice. Sprinkle chopped parsley on top.