Pesto Pasta Salad

I made this for the first time at the end of a long July, when it was too hot to actually cook anything properly and I had a bunch of cherry tomatoes on the counter that were this close to becoming a problem.

I'd had pesto pasta a thousand times, but cold — as a salad — somehow felt different. More summery. More honest. I threw in what was in the fridge : some raw ham I'd been meaning to use up, a ball of mini mozzarellas, half a red onion. Twenty minutes later, it was the best thing I'd eaten all week. My flatmate ate two bowls and asked me to make it again immediately.

There's a very specific trick that makes this work though, and I'll tell you about it in a second — because without it, your pesto will end up sitting in sad little clumps all over your pasta, refusing to cooperate. We've all been there.

Pesto Pasta Salad — What You Need to Know

Pasta salad is one of those dishes that looks dead simple but is full of potential pitfalls. The biggest one with pesto ? Pesto hates cold pasta. If you toss it in straight from the jar (or even straight from the mortar), it clumps. The oil seizes. You end up with pesto nuggets instead of an evenly coated salad.

The fix is embarrassingly easy : pasta water. Keep a few tablespoons of starchy cooking water before you drain your pasta, and mix it into your pesto before dressing the salad. The starch emulsifies with the oil and turns the whole thing into a smooth, glossy sauce that coats every single piece. This is the same technique as hot pesto pasta — it just works cold too.

The other thing worth mentioning : if you're using homemade pesto, you genuinely need less than with store-bought. Homemade is more concentrated, more fragrant, more everything. Five tablespoons is the right amount for homemade. If you're using a jar from the refrigerated section of the supermarket, I'd start at 7 and taste from there.

Pesto Pasta Salad — Recipe

Ingredients — Advice & key points

• Short pasta : Fusilli, farfalle, penne, rotini — anything with nooks and crannies that can hold onto the sauce. Long pasta just doesn't work in a cold salad, it slides right off. I usually go for fusilli.
• Cherry tomatoes : Cut them in half. This is not optional — whole cherry tomatoes in a pasta salad are an experience nobody asks for. Half is the move.
• Raw ham : Prosciutto crudo, Parma ham, Serrano — whatever your local deli has. Tear or cut it into small strips, not too thin. You want a bit of texture.
• Mini mozzarella balls : Also called ciliegine or bocconcini. I strongly prefer the mini version for this — they integrate into the salad way better than torn chunks of a big ball. If you can only find large mozzarella, tear it into rough pieces.
• Pesto : Ideally homemade — and if you haven't made it, this salad is a very good reason to start. The flavour difference is significant. If you're going store-bought, buy it from the refrigerated section, not the shelf-stable jar. And use more of it.

Cooking process — Advice & key points

• Cook your pasta al dente, and salt the water properly. 10g of salt per litre is the standard. Undersalted pasta water makes undersalted pasta makes an underseasoned salad — there's no fixing it later.
• Reserve your pasta water before draining. Two to three tablespoons is enough. Don't skip this step — this is what makes the pesto coat properly instead of clumping.
• Cool the pasta quickly. Once drained, spread it on a baking sheet or rinse briefly with cold water to stop the cooking and cool it down before adding the pesto. If the pasta is too hot, the basil in the pesto cooks slightly and loses its freshness.
• Mix the pesto with pasta water, unless your pesto is already quite liquidy. You can add it and mix it with pasta before adding the remaining ingredients -tomatoes, ham and mozzarella are a bit fragile and don't need to be manhandled.
• Taste and adjust salt at the end. The ham and pesto both bring salt, so go easy.