1. Preheat oven to 450 degrees F. Place potatoes in oven. Do not wrap in foil, you want the skin to be tough. Bake for 1 hour.
2. While potatoes are cooking, steam or boil the butternut squash until tender (steamed is better). Drain the squash. Remove the spuds from the oven and cut in 1/2.
3. Scoop the guts out and put into a big bowl. Make sure that you leave about 1/4 potato attached to the skin. Add the cooked squash, margarine, pepper, and a little sea salt to bowl.
4. Mash it all together until you get the consistency of lumpy mashed potatoes. Place skin halves on baking sheet and scoop mixture back inside each skin.
5. Bake in oven for 10 minutes. For crispy tops, coat top with melted margarine and place under broiler for 3-5 minutes.
Good eating! My non-vegetarian boyfriend thought that I had flipped my lid when I made him these! They really taste like they have cheese in them! And the color of the squash makes it look like it, too!