Polenta is cheap and easy — a caterers delight!
Bring the liquid to a boil in a heavy-bottomed pot on the top of the stove. Whisk in the polenta and salt. Cook very slowly over low heat stirring constantly with a wooden spoon until the spoon can stand up in the mixture. This usually takes about 20 minutes. Stir in the butter, mascarpone and maple syrup. Cover and keep warm. (If you are going to keep it a while, stir in 1/2 cup or more water.)
Peel, core and slice the apples in 1/2 inch slices. Melt the butter in a medium-sized frying pan over mod. high heat, add the sliced apples, sprinkle over the sugar. Continue to cook the apples over mod. high heat, turning occasionally, until the apples are golden and soft when pierced with a fork.
In a small frying pan, over mod. high heat, place the walnuts and cook, tossing until slightly toasted. Remove from heat.
To serve, place a serving of polenta in a bowl, cover with apples, sprinkle with walnuts and serve with maple syrup.
Serves 4 to 6.