The day before. Cut the beef into small pieces no bigger than a walnut and place them in a bowl where they will sit the whole night soaked into the marinade. To make the marinade, add the orange juice and lemon juice, mustard, salt and pepper and finish with a generous splash of extra virgin olive oil. Stir and cover with plastic wrap, then forget the meat in the fridge until the next day.
The next day. Drain the meat from the marinade and keep it aside. Cut the sausage and the bread into bite size pieces. Make the skewers alternating beef, sausage and bread.
Arrange the skewers in a baking dish, drizzle with extra virgin olive oil and bake them in preheated oven to 190°C for about 35 minutes, basting them frequently with the marinade.
Serve the skewers as soon as they are ready, with a side of baked or fried potatoes.