That depends on whether you slice it first or cook squash whole but generally it's going to take about an hour. Total cook time will vary slightly depending on the size but 4 lbs. is typical and I like to use a bit higher temperature to get it to fork tender too. If left whole you need no liquid. Sliced with squash cut side down it should be put into a dish with about 3/4 cup of water to moisten it during this time.