1. Melt butter in a large skillet over medium-high heat. Add mushrooms, 1/4 teaspoon salt, and pepper; sauté 3 minutes. Add garlic, and sauté 1 minute. Add wine, and reduce liquid by half, cooking about 8 minutes. Add cream and, if desired, nutmeg; simmer 2 minutes. Remove sauce from heat, and stir in cheese. Set aside.
2. Add 1 1/2 tablespoons salt to a large pot of water, and bring to a boil. Add pasta, and cook 1 to 2 minutes or until al dente. Add broccoli and asparagus, and cook 2 minutes. Add sugar snap peas, and cook 1 minute or until vegetables are crisp-tender. Drain, reserving 1/4 cup water.
3. Transfer to a separate skillet. Stir in tomato halves and fresh herbs, and gently toss pasta with sauce, adding reserved water as needed for moisture. Garnish, if desired.