2 Tbs. unsalted butter or olive oil
1/2 cup grated Parmesan cheese
1 medium onion, chopped (1 cup)
5 cups low-sodium vegetable broth
2 lb. fresh asparagus (36 to 40 medium-size spears), tips reserved, stalks cut into 1/2-inch pieces, divided
1 tsp. dried thyme
1/3 cup low-fat milk or heavy cream
1 Tbs. lemon juice
2 tsp. grated lemon zest
1. Preheat oven to 400°F. Line baking sheet with foil. Divide Parmesan cheese into 6 mounds on baking mat, and flatten using back of spoon. Bake 3 to 4 minutes, or until cheese melts into lacy rounds. Cool completely. Remove from baking sheet with spatula; set aside.
2. Melt butter in large saucepan over medium heat. Add onion, and sauté 5 to 7 minutes, or until soft. Add broth, asparagus stalks, and thyme; bring to a boil. Reduce heat to medium-low, cover pan, and simmer 15 to 20 minutes or until asparagus is tender.
3. Meanwhile, cook asparagus tips in boiling, salted water 2 minutes, or until just tender. Drain, and rinse under cold water. Set aside.
4. Purée soup in blender or food processor until smooth. Return to pan, and stir in milk, lemon juice, and lemon zest. Season with salt and pepper, if desired. Serve warm or at room temperature, garnished with asparagus tips and Parmesan crisps.