Pour generous amount of olive oil to cover bottom of a stock pot. Add 1/4 to 1/2 stick butter. Heat over low-medium heat. Add chopped onion. Cook until translucent. Clean fennel bulb and the fern (the fern is the top, finely-leafed portion of the fennel) under cold water and pat dry. Chop bulb, discarding tough outer layer. Add chopped fennel bulb to onion and continue to sautéover low heat, stirring occasionally. Peel squash and carrots. Cut squash into medium-size cubes; slice carrot. Add 1 teaspoon kosher salt and sprinkle with white pepper.
Turn heat to medium, add 1/4 to 1 cup wine to onion and fennel; cook until alcohol burns off, approximately 4 to 5 minutes. Add carrot and squash to pot. Add 4 or 5 cans of chicken stock and remaining butter. Cover and bring to a slow boil. Mince several sage leaves and chop reserved fennel fern. Add to pot. Reduce to simmer, and cook until vegetables are very tender. Flavor with a dash of cinnamon, cayenne pepper, curry powder, nutmeg, ginger, if preferred. Remove soup from heat and puree with hand mixer/blender.