1. Cut the chicken breast into bite-sized pieces about 2 cm large and place them in a bowl. Drizzle with lemon juice, cover with plastic wrap, and let marinate for about 30 minutes. 2. In a large pan, melt 50 g of butter over medium heat. Remove the chicken pieces from the marinade, lightly pat them dry with paper towels, and add them to the pan. Brown over high heat for 3-4 minutes until lightly golden on all sides. 3. Deglaze with white wine and let the alcohol evaporate. Season with salt and pepper, add a sprig of rosemary, and transfer the pan to a preheated oven at 200∘C. Bake for about 20 minutes, turning the chicken halfway through cooking. 4. Meanwhile, separate the grapes from the bunch, wash, and dry them carefully. Finely chop the shallot and sauté it in a saucepan with the remaining butter. Add the grapes and cook over low heat for about 15 minutes, adding a little water if necessary. 5. Once cooked, take the chicken out of the oven and return it to the stovetop over medium heat. Add the grapes with their seasoning and stir gently for a few minutes so that the flavors meld perfectly. 6. Transfer the chicken with grapes to a serving dish and serve very hot.