Arugula Pesto Pasta

Why This Arugula Pesto Pasta Works

As the pasta boils in salted water, the starch inside the noodles swells and softens. The pasta stays firm enough to chew but has a little bite, so it can hold onto the pesto instead of turning mushy. A bit of that surface starch also clings to the noodles after draining, which lets the oily sauce grab on instead of sliding off.

In the food processor, the arugula, pine nuts, and garlic break down into tiny pieces. Once the cheese and oil go in, the fat from the olive oil and pine nuts wraps around the chopped greens and cheese. Everything blends into a smooth, thick paste that doesn’t separate, so the oil doesn’t pool at the bottom of the bowl.

When the warm pasta is tossed with the pesto, the heat loosens the sauce just enough so it spreads into all the little gaps between the noodles. The rough surface of the pasta catches the bits of arugula and nuts, so every strand or piece ends up coated instead of having sauce only on the outside.

Mistakes To Avoid

Overcooking the pasta turns this into a mushy dish fast. Once the pasta goes past al dente, the softer surface soaks up the oily pesto and breaks apart, so the noodles clump together and the sauce feels heavy instead of silky.

Adding hot pasta straight to the pesto in the processor bowl can cause trouble. The heat wilts the arugula further and can make the cheese melt in sticky strings, so the pesto turns greasy and pasty instead of staying smooth and loose.

Skipping the slow stream of oil and dumping it in all at once often leaves the pesto separated. The solids and oil don’t blend properly, so the sauce looks broken, with oily pools and grainy bits instead of a creamy, even coating on the pasta.

Letting the pasta sit drained for too long before tossing means it dries out on the surface. The starch that helps the pesto cling tight forms a crusty layer, so the sauce slides off and collects at the bottom of the bowl.