Wash and dry the radishes, trim the ends, and place them in a tall, narrow container along with the shelled pistachios, previously washed parsley, cold water, and olive oil.

Use an immersion blender to blend the mixture in short bursts so the blades don’t heat up, until you reach your desired consistency.

If needed, add a few teaspoons of water, a little at a time, to avoid making the pesto too runny. Season with salt and use your pesto however you like!