Chicken with Onion Sauce
Rinse the broccoli rabe, trim and blanch 5 minutes in salted water and remove. Place in a pan with 1 tablespoon butter and cook over low heat until al dente and season with salt and pepper.
Peel the rhubarb and cut diagonally into 0.5 cm (1/8 inch) thick slices. Peel the onions and cut lengthwise into slices. Heat oil in a pan and sauté the onions with mustard seeds in it, add the sugar and caramelize, stir in the red wine and vinegar and simmer for about 5 minutes. Then add the rhubarb and simmer for another 3-5 minutes. Season with salt and pepper to taste.
Cut the chicken breasts into thin slices and brush with a little oil, season with salt and pepper and cook in a grill pan or on a hot grill about 1-2 minutes on each side. Spoon the sauce with the broccoli rabe on plates, top with the chicken slices and serve sprinkled with pepper.