Sauté mushrooms in butter in a large sauté pan over medium-high heat until golden brown. Stir in tomatoes and garlic. Sauté 1 to 2 minutes, or just until tomatoes soften slightly. Combine with broccoli, carrots, peas and crab meat.
Pour cream and wine into a large saucepan. Bring to a boil and reduce by 3 cups, stirring occasionally. Stir in Parmesan, basil and lemon juice. Season to taste with salt and pepper.
Steam crab legs: Place steam basket in large pot; fill pot with boiling water to depth of 3/4 inch. Place thawed Alaska Snow Crab split legs in basket; reduce heat and steam covered, about 5 minutes or until crab is thoroughly heated.
For each serving: Heat 1/2 cup cream sauce with 1 1/2 cups vegetables. Toss with 6 oz. cooked fettuccine. Arrange on a serving plate with 3 Alaska Snow Crab split legs. Sprinkle pasta with 2 Tbsp walnuts.Servings: 24