Preheat oven to 350 degrees F.
To prepare the onions, cut the onions into 4 wedges (quarters) leaving the top on so the pieces stay together. Gently saute the pieces in a pan until golden brown. Sprinkle the onions generously with caster sugar and roast in the oven until soft.
To make the polenta, cut the mushrooms in half and saute with oil in a pan until soft and brown and set aside. Cut the blue cheese into 1/4-inch cubes and set aside. Bring the chicken stock to a boil and add the polenta. Continue to stir while gently simmering until the polenta is soft and smooth, about 20 minutes. Add the cream and salt and pepper, to taste, and keep warm.
To assemble the dish, season the tenderloins with salt and pepper and sear in a hot pan until golden brown on all sides, about 3 minutes per side. Deglaze the pan with veal stock and reduce to a syrup consistency. Finish tenderloins in oven with onion pieces until desired degree of doneness is reached. Allow meat to rest for approximately 8 minutes. While tenderloin is resting, gently heat the polenta over low heat, adding mushrooms and blue cheese, and adjusting the seasoning 2 minutes before serving.
To serve, place a generous spoonful of polenta in the center of each plate, top with caramelized onions, and put tenderloins on top. Spoon stock reduction over and around the tenderloins and serve with steamed vegetables, if desired.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Terry White, Four Seasons Hotel, Dublin, Ireland