Prepare all the ingredients. Roughly chop the Parmesan and the sliced garlic clove in a food processor. Transfer the mixture to a tall blender cup.

Do the same with the walnuts.

Repeat with the arugula.

Add salt and pepper, then blend everything more finely with an immersion blender. Slowly drizzle in the olive oil while blending, and continue until you reach a smooth, creamy consistency. Blend to your preferred texture.

I used it as-is to toss with pasta. I love the slightly bitter and peppery flavor of wild arugula! If you have leftovers, portion the pesto onto parchment paper, freeze until solid, then transfer the pesto “balls” to a container to store in the freezer. Take out as many portions as you need each time.