The sauce for this light spring pasta is made with poached garlic and tofu, blended until velvety smooth and brightened with fresh herbs. You can top the pasta with freshly grated Parmesan cheese, if desired.
Bring large pot of lightly salted water to a boil.
Meanwhile, in small saucepan, combine broth and garlic; bring to a simmer over medium-high heat. Reduce heat to low. Cover and simmer until garlic is very tender, 15 to 20 minutes. Transfer to blender or food processor. Add tofu, olive oil, lemon juice, mustard, and salt and pepper to taste; process until smooth and creamy. Return to saucepan.Warm over low heat but do not boil. Stir in chives, tarragon, parsley and lemon zest. Cover and keep warm. (Sauce can be prepared ahead. Cover and refrigerate for up to 2 days. Reheat before continuing with recipe.)
Peel asparagus stalks, if desired, and cut into 1 1/2-inch lengths. Cut carrots into 1 3/4-by 14-inch sticks.
Add pasta to boiling water, stirring to prevent sticking. Cook, stirring often, until just tender, 9 to 11 minutes. While pasta is cooking, place carrots in a steamer basket over boiling water. Top with asparagus. Cover and steam until tender, 4 to 5 minutes. Drain pasta and transfer to large, warm bowl. Add vegetables and reserved herb sauce; toss to coat. Serve hot with lemon wedges for squeezing, if desired.