Preheat oven to 375 degrees. In a large mixing bowl, place flour, sugar and walnuts. Add 1/2 cup cold milk and slowly add rest of milk, stirring constantly to avoid lumps to form in batter. Grease pan with 1 tablespoon oil and pour in batter. Drizzle top with remaining oil and distribute rosemary evenly over top. Bake for 45 minutes, or until a toothpick pierced in the center comes out clean. While castagnaccio is cooking, place grapes and sugar in a small saucepan over medium heat. Cook until quite soft and bubbly, about 10 minutes. Remove castagnaccio from the oven and serve either warm or cool with grape sauce. Source: MOLTO MARIO with Mario Batali From the TV FOOD NETWORK - (Show # MB-5725) Per serving: 352 Calories (kcal); 11g Total Fat; (26% calories from fat); 4g Protein; 62g Carbohydrate; 17mg Cholesterol; 60mg Sodium Food Exchanges: 0 Grain(Starch); 0 Lean Meat; 0 Vegetable; 0 Fruit; 2 Fat; 4 Other Carbohydrates Recipe by: Mario Batali Converted by MM_Buster v2.0n.