Roasting: Preheat oven to 400 F (200 C). Wash squash with a brush and pat dry.
Cut off ends and then in half crosswise. Place halves upright and peel the skin off with a vegetable peeler or a sharp knife.
Cut squash into quarters and remove both the seeds and strings using a spoon.
Cut into ¾ to 1–inch cubes. Place them into a bowl and mix with olive oil, garlic, rosemary, and salt and pepper until coated.
Spread mixture into a large baking sheet (preferably lined with foil for easy cleaning).
Roast for about 35-40 minutes or until fork-tender and caramelized.
Boiling: Wash squash with a brush and pat dry. Cut off ends and then in half crosswise. Place halves upright and peel the skin off with a vegetable peeler or a sharp knife.
Cut squash into quarters and remove both the seeds and strings using a spoon. Cut into ¾ to 1–inch cubes.
Place squash in a pot and fill with enough water to cover by 1-2 inches above the squash. Season with salt and boil over high heat for about 12-15 minutes or until fork-tender.
Drain or remove cooked squash with a slotted spoon. You may serve with butter while still hot or a hint of extra virgin olive oil.
Crockpot: Wash squash with a brush and pat dry. Place whole squash in the slow cooker (with or without stem), close lid, and cook on high for 4 hours or on low for 8-10 hours. There is no need to pour water in the bottom to cook it.
Let it cool just enough to handle and cut in half lengthwise. Remove seeds and strings and then scoop out the flesh. That is how to cook butternut squash in the crockpot easily!
Instant Pot: Wash squash with a brush and pat dry. Cut off ends and then cut in half crosswise.
Put each half upright and cut into quarters. Remove seeds and string using a spoon.
Place steam basket into the Instant Pot and pour in 1 ½ cups of water. Place squash quarters on top of the steam basket, lock the lid, secure the valve, and cook on high pressure for about 6-7 minutes. Depending on your pressure cooker, you may have to press the steam button and manually set to 6 or 7 minutes.
Remove quarters with tongs and scoop out the flesh. To serve it as baby food, just smash or purée the cooked flesh.
Microwave: Wash squash with a brush and pat dry. Using a paring knife, make slits around squash to vent.
Place whole squash in a microwave-safe dish and cook for about 10-12 minutes (1200 Watts) or more depending on the potency of your microwave.
Check if tender enough by pricking the cooked squash with a fork. Allow it to cool just enough to handle.
Cut cooked butternut squash in half and remove seeds and strings with a spoon. Cut into slices or cubes, or scoop out the flesh.