Preheat oven to 375°F
Rinse lentils and place in a small pot with 2 cups of water. Bring to a boil. Reduce heat to low, cover and simmer 20 minutes, or until water is absorbed and lentils are very soft.
While lentils are simmering, bring a medium pot of salted water to a boil. Add chopped dandelion greens and blanch for 1-2 minutes. Strain out through a colander or mesh strainer and immediately rinse in cold water to stop further cooking. Leave greens in strainer and set aside over a bowl or pot to drain completely.
Heat oil in a medium skillet or sauté pan over medium heat. Add bison and cook until completely brown. Remove from pan with a slotted spoon and set aside. Reserve 2 tbsp of drippings in the pan and drain any excess.
Add white onion to pan and cook until translucent, about 3 minutes. Add green onions and red bell pepper. Sauté for another 5 minutes. Add drained dandelion greens. Cook for an additional 2 minutes, stirring frequently to ensure the greens mix thoroughly with the other vegetables.
Return bison to the pan. stir in spices and coat thoroughly. Stir in cooked lentils. Continue cooking for another couple of minutes, until the bison is fully reheated.
Using a sharp knife, cut a circle in the top of the kabocha around the stem to create a lid (jack-o-lantern style). Scrape out and discard the seeds and stringy pulp from inside the squash, including any attached to the lid.
Brush the inside of the kabocha with a little bit of oil. Spoon bison mixture into the cavity, packing it in tightly to ensure there are no air pockets. Replace the top of the kabocha, then set the entire squash on a rimmed baking sheet.
Bake at 375°F for 1 hour, or until kabocha is fork tender.
Serve by cutting into wedges or using a large serving spoon to portion out chunks of kabocha and filling. Or just set it in the center of the table and pass out some forks for everyone to share.