Boil the pasta. Bring a large pot of salted water to a rolling boil. Cook the pasta until just al dente according to package directions. You want it tender but still with a little bite.

Blanch the peas the easy way. In the last 1 to 2 minutes of the pasta’s cook time, add the frozen peas to the pot. They’ll brighten and soften quickly without getting mushy.

Reserve pasta water. Before draining, scoop out about 1/2 cup of the starchy pasta water. It will help loosen the pesto and create a silky coating.

Drain and cool slightly. Drain the pasta and peas, then transfer to a large bowl. Toss with 1 tablespoon of olive oil so the noodles don’t stick. Let it cool for 5 to 10 minutes—pesto clings better when the pasta isn’t piping hot.

Make the pesto dressing. In a small bowl, mix the pesto with 1 to 2 tablespoons of olive oil, the lemon zest, and 1 to 2 tablespoons of lemon juice. Whisk in a splash of reserved pasta water until it’s creamy and pourable.

Toss to coat. Pour the pesto mixture over the pasta and peas. Add the parmesan and toss until everything is evenly coated. If it seems thick, add more pasta water a tablespoon at a time.

Add extras. Fold in cherry tomatoes, torn basil, and nuts if using. Taste and season with salt, black pepper, and a pinch of red pepper flakes if you like a little heat.

Rest and serve. Let the salad sit for 10 minutes to meld. Serve at room temperature, or chill for 30 to 60 minutes for a cooler, slightly more set version. Finish with extra parmesan and a drizzle of olive oil.