The day before you want to serve your Beouf Bourguignon, place the meat in a bowl with the sliced vegetables. Add the crushed garlic cloves, bouquet garni, peppercorns and red wine and marinate in the refridgerator for 24 hours.
Preheat the oven to 180°C.
Drain and separate the vegetables, the marinade, and the meat (set aside the bouquet garni). Pat the meat dry, then heat a little oil in a large oven proof pan or casserole dish, add the meat and fry until brown. Remove from the pan and drain the excess fat.
Add a little more oil to the same pan and brown the vegetables. Add the tomato paste, the browned meat and the flour. Mix well and place the pan in the oven for a few minutes to cook out the flour.
Bring the marinade liquid to the boil and skim the top. Strain the liquid over the meat and mix well. Add the brown veal stock, the bouquet garni, blanched bacon rind and season. Return to the boil then cover the pan with a lid and cook in the oven for approximately 1¼ hours. Once the meat is cooked, remove from the sauce and keep warm.
Strain the sauce and reduce to the desired consistency. Place the meat back into the sauce and stir to combine. Remove from the heat, set aside and keep warm.
Add the oil to a frying pan set over a medium-high heat. Cut the bacon into lardons, add to the pan and cook until lightly brown and crispy.
Add the oil and butter to a pan set over a medium heat. Sauté the mushrooms, then season.
Place the onions in a saucepan; add butter, pinch of sugar, salt and enough water to cover the onions. Cook over high heat to increase the speed of evaporation, allowing the sugar and butter to caramelise. Once a caramel forms, swirl the onions by shaking the pan so they evenly colour.
Cut the sandwich bread slices in two diagonally then cut into heart shapes. Cook in oil and butter (or clarified butter) until lightly golden.
Decorate with flat-leaf parsley and serve in your favourite serving dish with the croûtons on the side.