Bring a kettle of water to a boil.

To heatproof bowl, add cashews and sunflower seeds. Pour over just-boiled water and set aside for 20 minutes.

Drain cashews and sunflower seeds and add to blender or food processor along with water (or dairy-free milk), lemon juice, vinegar, nutritional yeast, salt, and garlic. Blend, stopping to scrape down sides of container as needed, until mixture is as smooth as possible. If very thick, add additional water or dairy-free milk, 1 Tbsp at a time, to arrive at a thick, spreadable consistency.

Transfer to bowl and fold in chopped herbs. Serve immediately or store in an airtight container in refrigerator for up to 3 days.