Pulse the garlic clove in a large food processor just to break it up. Add the cashews and pulse 2-3 times. Add basil and juice of two lemons. Turn on the processor and drizzle in 1/4 of olive oil while running. Stop processor and use a spatula to scrape down the sides, then process again. Drizzle additional oil as needed but only until you have a thick paste. Season to taste with salt.

Divide the pesto into 2 small mason jars and drizzle olive oil on top. Refrigerate for up to a week or freeze.