Preheat oven to 350º F

Cut the kabocha in half and scrape out the seeds and stringy guts with an ice cream scooper. Cut kabocha halves into large chunks and drizzle with extra virgin olive oil; making sure they are well coated. Lay the chunks out flesh side down onto a baking sheet making sure not to overcrowd the pan. Put in the middle rack of the oven and roast for 30-45 minutes.

When ready, transfer to a plate and let cool. Then scrape the flesh out and discard the skin.

While the kabocha is cooking, Fill a tea kettle with a lot of filtered water and turn it on. When the water is ready, measure out 6 cups and throw the Kombu in. Let it steep until the water gets cool. About 30-45 minutes. Discard Kombu and keep the liquid.

Add the butter to a large heavy bottomed pot and melt over medium heat. Add sliced leeks to the pot and cook until they begin to brown.

Add nutmeg and cinnamon. And cook for a 30-60 seconds.

Add kabocha and cook for 2 minutes.

Add the Kombu stock and bring to a boil.

Turn down to medium and purée with an immersion blender.

Whisk in the milk and the miso paste and simmer until the miso has dissolved and thickened. The soup should be reasonably thick.

Garnish with chives.