Chef John's Pasta Primavera

Fill a large bowl with ice and cold water; set next to stovetop. Bring a large pot of lightly salted water to a boil. Hold basil bunch by stems; dip basil leaves in boiling water until bright green, about 2 seconds. Immediately immerse basil in ice water for several minutes to stop the cooking process. Drain well. Remove basil leaves from stems; discard stems.

Combine basil leaves, 1 cup chicken broth, 1/2 cup olive oil, and garlic together in a blender; blend until smooth.

Return the same pot of water to a rolling boil. Cook fettuccine at a boil until tender yet firm to the bite, about 8 minutes. Drain; transfer to a large bowl.

Meanwhile, heat 2 tablespoons olive oil in a large saucepan or Dutch oven over medium heat. Add leek and green onions; cook and stir until softened, about 5 minutes. Add jalapeño and salt; cook and stir until jalapeño is soft, about 5 minutes. Increase heat to medium-high. Stir in remaining 2 cups chicken broth, zucchini, sugar snap peas, and English peas; bring to a simmer and cook for 5 minutes. Add asparagus; cook until asparagus is soft, about 3 minutes.

Add 1/4 cup basil-garlic purée to vegetable mixture; cook and stir until heated through, about 1 minute. Remove from heat.

Pour vegetable mixture over fettuccine; toss. Add remaining basil-garlic purée, sprinkle with Parmesan cheese, and toss briefly to combine. Wrap bowl tightly with aluminum foil; set aside until fettuccine and vegetables soak up most of the juices and oil, about 5 minutes. Toss.