Mashed potato squash is similar to acorn squash with a mild, potato-like flavor. It's easy to cook and makes a great side dish.
Preheat oven to 375° F.
Place squash on a cutting board. Using a chef's knife, cut off about a ¼-inch off the root and stem end. Keep your fingers away from the blade. Stand the squash up on one of those ends and cut in half, from top to bottom.
Using a spoon or ice cream scoop, remove the seeds.
Brush olive oil on the cut-side of the squash and season with salt and pepper. Place the squash, cut-side down, on parchment-lined baking sheet.
Roast until tender, about 45 minutes. The squash should be tender and soft when pierced with a fork.
Eat right away or mash. To mash, scoop the squash from the shell and place in a medium mixing bowl. Add the milk and butter. Mash with a potato masher or handheld mixer until soft. If needed, add additional milk until creamy. Season with salt and pepper to taste.