Preheat oven to 400°F. Line a baking tray with parchment paper or foil.
Cut squash in half from stem to the bottom. Scrape seeds and soft membranes and discard. Place flesh side up on baking tray.
Add half of the butter to each cavity, spread with a spoon, and sprinkle each with half of the brown sugar. Sprinkle with salt and pepper (or season once squash is cooked if you prefer).
Bake uncovered for 40 to 50 minutes or until the squash is fork-tender and cooked to desired tenderness.
Serve ¼ to ½ a squash per person.
Notes
Substitute maple syrup or honey in place of brown sugar if desired.
Modify the bake time depending on how firm or soft you want the squash to be. Check regularly after 40 minutes.