Place the rosemary, arugula, nuts, cheese, garlic, one tablespoon of lemon juice, and salt in the bowl of a small food processor.
Pulse until coarsely combined. Keep the lid on and slowly drizzle the olive oil through the pour spout while continuing to pulse.
Once the pesto is ground into a fine paste, taste and add additional lemon juice and salt as desired.
Notes
This recipe makes about 1 cup or 16 tablespoons. Each serving is about a tablespoon.Store the arugula and rosemary pesto in an airtight container or a mason jar in the refrigerator for up to two weeks. For extended storage, freeze the pesto for up to six months. Portion it into ice cube trays or small containers, top with a layer of olive oil, and seal tightly.Pesto is usually used at room temperature or slightly chilled, so generally, you don’t need to reheat it. If necessary, gently warm it in a saucepan over low heat, stirring frequently to preserve its texture.