Kombu is a type of kelp or seaweed that can improve the digestibility of beans and legumes. It can be found in some grocery and most "health food" stores.
Rinse and soak the lentils over night in water to cover plus one inch. The next day, replenish the water to cover by at least one inch. If using Kombu, add it now. Scrub the squash, cut into 4-6 chunks and remove seeds, and place on top of the lentils. Cover. Simmer the lentils and squash, until the squash is tender, maybe 1/2 hour.
Remove the chunks and let cool. Take off the peel, mash, and return the squash to the pot. Add the vegetables to the pot with the stock and hot oil. You may want more stock to get it the desired thickness. Simmer about 1/2 hour and serve.