Chop up all the veggies.
In a large pan, heat the olive oil over medium heat, then add the leeks, onions, and garlic. Cook for 5 minutes, stirring occasionally, until the onions are soft, then add the cauliflower and apple and cook for a few minutes more.
Add water to halfway cover the veggies and bring to a boil. Reduce the heat once it starts to boil and simmer for about 10 minutes with a tight-fitting lid, until you can stick a fork into the cauliflower pieces easily.
Stir in the almond butter, then scoop out the veggies into a blender (I had to do two blender batches). You may need to add a little bit more water to be able to blend it into a smooth soup.
Pour into a medium-sized pot. Taste to adjust salt and pepper if needed. Serve as a warming appetizer to dinner, or as a lunch in itself. This soup reheats nicely too, if you have leftovers – just gently heat over the stove or microwave a bowl for yourself. So good!