Gather all ingredients.
Preheat the oven to 350 degrees F (175 degrees C).
Place acorn squash halves cut-side down onto a cookie sheet. Bake in the preheated oven until flesh begins to soften, about 30 to 45 minutes.
Remove squash from the oven and transfer one squash half, cut-side up, to a deep baking dish. Spoon butter and brown sugar into the cavity. Place remaining squash half, cut-side down, over top to seal.
Return to the oven and continue to bake until flesh is soft, 30 minutes.
Serve hot and enjoy!
