Step 1: Bring a large pot of heavily salted water to a rolling boil. Add the pasta and cook according to package directions until al dente. Before draining, reserve 1 to 1.5 cups of the starchy pasta water. Drain the pasta and set aside.
Step 2: While the pasta cooks, heat the olive oil in a large skillet or Dutch oven over medium heat. Add the minced garlic and sauté for 30-60 seconds until fragrant, being careful not to burn it.
Step 3: Add the asparagus pieces to the skillet and cook for 3-5 minutes, stirring occasionally, until bright green and tender-crisp. If using fresh peas, add them now and cook for another 2-3 minutes. If using frozen peas, add them during the last minute of cooking with the asparagus.
Step 4: Pour about 1/2 cup of the reserved pasta water into the skillet. Stir in the lemon zest and about half of the fresh lemon juice. Add the unsalted butter and stir until melted and a light sauce forms. Season with salt and freshly ground black pepper.
Step 5: Add the drained pasta to the skillet with the vegetables and sauce. Toss everything together, adding more reserved pasta water a tablespoon at a time until the sauce is creamy and coats the pasta well.
Step 6: Remove the skillet from the heat. Stir in the grated Parmesan cheese, the remaining fresh lemon juice, and the chopped fresh parsley and mint (or dill). Toss gently to combine.
Step 7: Taste and adjust seasonings as needed. Serve immediately, garnished with extra Parmesan cheese and a sprinkle of fresh herbs if desired. Enjoy your vibrant spring pasta!