Peel and chop potatoes into ¾-inch chunks.

Cut cauliflower into small florets.

Peel and chop garlic cloves.

For the leeks, cut off the dark green leaves, so that only the white and light green parts of the leek remain. Rinse well. Remove the outside leek layer, and check to see if there is dirt between the remaining layers. If not, just slice thinly. If there is more dirt, slice thinly and place leek slices in a bowl of cold water for 5 minutes. Remove leeks with a slotted spoon, trying not to disturb the dirt at the bottom of the bowl, and pat dry.

Heat olive oil in a large saucepan over medium heat.

Add chopped garlic, sliced leeks, and miso paste. Cook for 2-3 minutes, stirring frequently, until vegetables are softened but not browned and miso is fully incorporated into the vegetables.

Add potatoes and cauliflower and cook for another 2 minutes, stirring frequently.

Add vegetable stock, and bring to a simmer over medium heat. Cook for 15-20 minutes, with the pot partly covered, until potatoes and cauliflower are tender.

To blend, either use an immersion blender directly in the pot, or let soup cool slightly before pouring into a regular blender.

Bring soup back to a simmer after blending, and add heavy cream. Stir in salt.

Heat gently for 5 minutes, to allow the flavors to meld.

Taste, and add additional salt and pepper, as needed. Garnish with a swizzle of olive oil and a sprinkle of sliced green onions, if desired.