Trim the woody ends from the asparagus and cut the stalks into 1-inch pieces, then separate about 3 inches of the top tender pieces and set aside—these will stay fresh and bright in the final dish. Measure out your basil, lemon juice, and other ingredients. Toast the 2 tablespoons of pine nuts in a dry pan over medium heat for 2-3 minutes until fragrant, shaking occasionally to prevent burning, then set aside. I like to toast pine nuts just before using them because they release their oils and become so much more flavorful than raw nuts.

Bring a large pot of salted water to a boil and add the asparagus pieces (including both the tender tops and thicker stalks). Boil for 4 minutes until just tender-crisp, then remove with a slotted spoon and rinse with cool water to stop the cooking. Set aside the tender asparagus tips separately. In the same boiling water, cook the pasta according to package directions until al dente. Before draining, reserve 1/2 cup of the starchy pasta water—this is liquid gold for adjusting your pesto sauce's consistency. Drain and lightly rinse the pasta, then transfer to a large bowl.

In a food processor, combine the 4 garlic cloves and the toasted pine nuts from Step 1, pulsing until finely chopped. Add the lemon juice, basil, salt, nutritional yeast, and the cooked thicker asparagus stalks (not the tender tops—save those for texture in the final dish). Pulse and blend until smooth, then slowly add 3-6 tablespoons of the reserved pasta water until you reach a pourable sauce consistency. I find that starting with 3 tablespoons and adding more as needed gives you better control over the thickness than dumping it all in at once.

Pour the asparagus pesto sauce from Step 3 over the warm pasta in the bowl, then fold in the tender asparagus tips from Step 2 and the diced tomatoes. Toss gently but thoroughly to coat all the pasta evenly. Taste and adjust seasoning with salt and pepper as needed, keeping in mind that the nutritional yeast and pesto already contain saltiness. Top with the remaining 3 tablespoons of pine nuts for added crunch and richness.