Trim excess fats from duck breast and slice into fine strips. Soak the porcini mushrooms in the red wine, allow softening. Stew the sliced leek and chopped garlic with butter until wilted. Pour in the red wine with the porcini mushrooms and allow evaporation. Stir in the tomato pulp and chopped sage leaves, season with salt and pepper and simmer for 10 minutes. Grill the duck breast slices separately, season with salt, pepper and truffle oil. Cook the fusilli in plenty boiling salted water. Toss the pasta in the porcini-tomato sauce. Serve with the grilled duck breast, shredded burrata and toasted pine nuts.