1 pound fresh asparagus
3/4 cup chopped onion
1/2 cup vegetable broth
1 tablespoon butter
2 tablespoons all-purpose flour
1 teaspoon salt
1 pinch ground black pepper
1 1/4 cups vegetable broth
1 cup soy milk
1/2 cup yogurt
1 teaspoon lemon juice
1/4 cup grated Parmesan cheese