For the marinade: Using a big bowl, layer the beef, orange peels, onions and carrots until all used.
Add the wine and top with 3 bay leaves and the peppercorns.
Wrap tightly with plastic wrap and let marinate sit overnight in the fridge.
Drain the beef in a colander with a bowl underneath, reserving the marinade.
Seperate marinade and marinade ingredients into two separate bowls
Place the flour, pepper and some salt in a shallow plate and, working in batches, toss the beef in the flour, shaking off any excess.
To sear: In a saucepan over medium heat, Add unsalted butter and olive oil
Working in batches, add the coated beef to the pan and sear for 8 minutes per batch.
Transfer the beef from the pan to a bowl and repeat with the remaining beef and seasoned flour until all the beef has been browned.
For the stew: Melt 3 tablespoons of the butter and olive over medium heat in the same pot used to brown the beef and add garlic and onions.
Cook until the onions are slightly golden, about 4 minutes.
In a pot, add wine marinade, beef, tomato paste, marinade ingredients, dried mixed herb, bouquet garni, beef stock cubes and mushrooms. cover and simmer for 3 hours
You can serve this stew with pasta, mash potato or even rice! Garnish with parsley.