Pasta with Green Beans, Potatoes & Pesto

This pasta with pesto is the classic Ligurian preparation called pasta alla Genovese, a dish that confused American cooks for years. Why would you cook pasta with potatoes? The answer is that the starchy potato chunks bind the pesto to the pasta in a way no amount of pasta water alone can manage, while the green beans add fresh vegetal contrast. It’s an unexpected combination that the Genoese figured out centuries ago.

The traditional method uses trofie or trenette pasta, but penne or fusilli work beautifully and are easier to find. The corkscrew shapes catch pesto in their spirals.

Blanch the green beans (boil briefly, then plunge into ice water) so they retain their bright color and slight crunch. Add them raw to the hot pasta and they go drab and limp.

Parboil the Yukon gold potatoes until just fork-tender, not mushy. They get briefly heated through with the pasta but shouldn’t break down. Cubed into ½-inch pieces is the right size; bigger and they don’t integrate, smaller and they disappear.

Walnut oil instead of olive oil for the saute is a quietly genius upgrade. It echoes the toasted walnuts garnishing the dish and adds a layer of nutty depth.

Don’t reheat the pesto. Pesto is a raw sauce; cooking it makes it bitter and dulls the basil’s bright color. Just warm everything through; if it needs more loosening, add a splash of pasta cooking water.

Pro Tips

• Toast the walnuts at 350°F (175°C) for 6 minutes before adding for noticeably deeper flavor.
• Reserve a cup of pasta cooking water before draining. The starchy water is the best thinner for pesto if the sauce gets too thick.
• Use freshly grated Parmigiano-Reggiano, not pre-shredded. Pre-shredded has anti-caking agents that prevent it from melting smoothly.

Variations

• Use store-bought pesto for a faster weeknight version, or make your own with fresh basil, pine nuts, and Parmesan.
• Substitute pine nuts for the walnuts to stay closer to traditional pesto territory.
• Add a squeeze of fresh lemon at the end for extra brightness.