Wash and slice the leek into ¼-½" slices. Slice the cabbage into thin strips.
1 leek, ½ pound green cabbage
Place the leeks and cabbage into a pan that will fit in your pressure cooker or wrap them loosely in aluminum foil. Put the pan of veggies on a sling and set on top of the potatoes. If using aluminum foil, set the foil packet on top of the potatoes.
Put the pressure lid on and turn the valve to seal. Set the pressure to high for 2 minutes. When the time is up, allow the pot to natural release for 5 minutes (this means do nothing for 5 minutes.). Then release the remaining pressure by moving the valve to vent.
Remove the lid and the pan or foil with leeks and cabbage. Set aside for later.
If you are using a stainless steel inner pot, use the immersion blender right in the pot to puree the potatoes. If your pot is ceramic, transfer the potatoes and liquid to a deep container and puree the potatoes with the immersion blender until smooth.
Add the potato puree back into the inner pot and use the keep warm function or low sear/sauté. Add in 1 cup of heavy cream and stir to combine.
1 cup heavy cream
Add in the leeks and cabbage with the liquid. If you have more than ¼ cup of liquid in the pan with the leeks, then only add in ¼ cup at first. You can add the rest if you need to thin the soup more. Stir well.
Taste for seasonings and add salt and pepper if desired. Ladle into soup bowls and top with sliced green onions for garnish.
You can use a food processor or blender if you don't have an immersion blender, just be sure to let the potatoes and liquid come to room temperature before blending with anything other than an immersion blender.You can also use a potato masher, but your soup won't be as smooth. A potato ricer will work as well, but you will have strain the potatoes first. Stovetop InstructionsBring a large pot with 5 cups of chicken broth to a boil and add in the chopped potatoes and salt. Boil until the potatoes are fork tender, this takes about 15 minutes or so. You can sauté the cabbage and leeks separately or if you have a steamer basket that fits on top of your pot, steam them on top of the potatoes. Puree the potatoes and cooking liquid with an immersion blender. Add in the leeks and cabbage. Add enough cream to get the desired color and consistency you want. Taste for seasonings and serve. Top with green onions for garnish.