Toast the pine nuts: In a dry skillet over medium heat, toast pine nuts for 3–4 minutes until golden and fragrant. Shake the pan often. Transfer to a plate to cool.

Boil the pasta: Bring a large pot of salted water to a boil. Cook rigatoni until just al dente. Reserve at least 1 cup of pasta water before draining.

Make the pesto base: In a blender or food processor, add arugula, basil, garlic, cooled pine nuts, lemon zest, lemon juice, 1 teaspoon salt, and a few grinds of pepper.

Blend with oil: With the machine running, stream in olive oil until smooth and creamy. If using, add nutritional yeast. Adjust seasoning with more lemon, salt, or pepper. If it’s too thick, add a splash of pasta water to loosen.

Warm the tomatoes: In the same pasta pot or a skillet, add a drizzle of olive oil and the halved cherry tomatoes with a pinch of salt. Cook 2–3 minutes just until they start to soften and release juice. Don’t overcook.

Combine: Return drained rigatoni to the pot with tomatoes. Add pesto and 1/4 cup pasta water. Toss over low heat for 1–2 minutes until glossy and well coated. Add more water as needed for a silky sauce.

Finish and serve: Taste and adjust with extra lemon, salt, and pepper. Top with extra arugula, more toasted pine nuts, and red pepper flakes if you like heat. Serve immediately.