Trim stems off squash and cut each in quarters using a cleaver or large chef's knife to cut, hitting back of knife with a mallet to force it through squash, if necessary. Scrape away seeds. In a large kettle, bring 2 quarts of water to a boil. Add squash sections and cook until tender, 10 to 15 minutes. Remove from water, sprinkle with a little mace and pepper.