Place almonds in boiling hot water for 5 minutes. Then drain the water and pinch the almonds to remove the skin, it will come out easily. Set aside.
Press the saute button on the Instant Pot. Once it displays hot, add the olive oil and then the chopped garlic and onion. Saute for 2 minutes until the onions soften.
Then add the chopped celery, broccoli florets and blanched almonds. Toss to combine.
Add 1.5 cups (12 oz) water, salt and close the lid. Before closing lid, make sure there's nothing stuck at the bottom of the pot so scrape if there's anything with your spatula.
Press the manual or pressure cook button and cook on high pressure for 5 minutes. Let the pressure release naturally for 10 minutes and then quick release the remaining pressure.
Open the pot and puree the soup using a hand blender or if using a regular blender like I did, wait for the soup to cool down for 10 to 15 minutes or so and then transfer the contents to the blender. Do not puree in a blender when the contents are super hot, it might blow up all over.Puree to a smooth consistency.
Transfer the soup back to the pot (you don't need to do this if you used a hand blender obviously) and press the saute button.
Add milk and stir. I used coconut milk here but you can use any milk of choice.
Add additional 1 cup water (8 0z) water. This might seem a lot but the soup thickens as it cools so this much water is perfectly fine.
Stir in black pepper and white pepper powder. Let the soup simmer for 2 to 3 minutes on saute.
Serve the broccoli almond soup hot. You can squeeze some lemon juice if you want a tang. I did not add any.
Stove-top instructions
First blanch the almonds in the same way as directed and set aside. In a pan heat olive oil, then add garlic and onion to it and saute for 2 minutes. Add the celery, broccoli and blanched almonds along with 1 to 1.5 cups water. Let it simmer for 10-15 minutes until broccoli is very soft. Let mixture cool down and then transfer to a blender along with 3/4 cup milk and puree. Transfer the soup back to the pan on medium heat. Add salt, black pepper, white pepper and let it simmer for 2 to 3 minutes. You may adjust the consistency of the soup at this point. Serve hot!
Video
Notes
In theory, you can replace the almonds with cashews however I would recommend using the almonds if possible. The almond and broccoli go really well together.