I was in my late 40's when I learned to love chestnuts. That is, very recently, 2022. I'd never had them, okay?! My partner decided to throw some onto our CSA order one week and, while they take some work, they were a complete hit with both of us. He had also thrown some red kuri squash on an order, since we had never tried that either. 

The chestnuts got 'et that week, and the kuri squash was sitting there waiting for inspiration. I decided to get more chestnuts last week, throw in a butternut squash, and make some warm, creamy soup! Cross-referencing other recipes, this is what I ended up making (this would work with a wide variety of squash, this is just what we had):

1 lb chestnuts
1 small-medium red kuri squash
1 small-medium butternut squash
1 small shallot, fine dice
3 cloves garlic, minced
4-5 leaves of fresh sage, minced (2-3 tsp fresh, 1 tsp dried or to taste)
1 Tbsp butter
1 cup veg or chicken stock
3/4 cup cream
a splash of dry white wine
salt and pepper
Optional: goat cheese or creme fraiche for garnish

Score and roast chestnuts
Roast nuts on a rack-lined sheet pan in a 450 degree oven for 35 minutes or until tops are peeling back. Put chestnuts in a kitchen towel, squeeze to crack/release shells. When cool enough to handle, extract the meat and remove papery skin as well. Finely rough-chop nuts and set aside. Meanwhile...

Roast squash in 450 degree oven.
Cut butternut squash in half and scoop out seeds, oil lightly and place face down on a foil-lined baking sheet. Cut red kuri squash in quarters, scoop out seeds, and then cut one more time into eighths. Oil and place on the same sheet pan. Roast for 25-40 minutes until soft and mashable. The red kuri was done before the butternut squash, so I just removed them to a plate and let the butternut squash continue a bit longer. Scrape flesh into a bowl and mash up. You don't have to mash too much here, since you'll be blending the soup more later.

Cook shallots and garlic.
Melt butter in a pan over medium heat, cook shallots a few minutes, add garlic and cook until fragrant. Add sage and chestnuts, to bloom the sage a bit and warm and soften the chestnuts further, 1-2 minutes. Add more butter if it seems too dry. There's always room for more butter!

Put it all together.
Add squash, stock, shallot/garlic/herb/chestnuts mix to a pot and stir together. Splash some white wine, and add cream a bit at a time, saving some back if you're not sure of the consistency. Before soup is hot, use immersion blender or regular blender to blend together all ingredients until smoothed (mine still had small chunks of chestnut in it, that was fine with me!) Never blend piping hot soups, it is a splash/burn risk. Blend while warm, then heat to desired temperature once it is blended, adding more cream if needed to reach desired consistency. Mine was a bit thick, but you may want yours thinner. Add salt and pepper while heating, to taste. I like a lot of fresh ground pepper in mine, to counterpoint the sweetness of the squash and chestnuts.

Ladle soup into bowls, top with goat cheese or creme fraiche as desired.

This goes great with a rustic, crusty bread if you have it!

I was amazed at how naturally sweet this soup was. Some recipes call for a little sugar in them, and I can't imagine needing it, with the sweetness of the squash and nuts already being so strong.