Using the Saute function, heat the olive oil, then saute the leeks until they are very soft, stirring often.
Cancel the Saute function and add the potatoes, vegetable broth, bay leaf, and herbs de provence to the Instant Pot. Give the ingredients a stir, then close and lock the lid.
Set the Pressure Cooker function on high for 4 minutes.
While the soup cooks, place the cashews and water in a high-speed blender. Blend until completely smooth, scraping down the sides of the blender as necessary. Set aside.
After the 4 minutes on the Instant Pot are up, quick release the pressure.
Once the pressure is fully released, remove the lid and carefully discard the bay leaf.
Using an immersion blender, puree the soup until completely smooth.
Slowly stir in the blended cashew mixture. Season the soup with salt, to taste.
Garnish the bowls of soup with sliced green onions or chives, if desired, and enjoy!
If you don't have a high-speed blender, soak the cashews in hot water for 3o minutes or longer to soften before blending.If you don't have an immersion blender, you can transfer the soup to a regular blender in batches, being sure to vent the lid so the steam can escape.This recipe serves 4 people. If you want to double the recipe, the 4 minute cooking time will remain the same. However, it will take longer for the Instant Pot to come up to pressure.Leftovers can be stored in the refrigerator for a few days and reheated on the stove or in a microwave.