I usually cook spaghetti squash in the Instant Pot, so I didn't think to try cooking one in the slow cooker until recently. The topic has already been covered by other websites, but I haven't seen anyone mention what I experienced after cooking several squashes— both whole and in half— so I thought I'd share to help you avoid any mushy results at home.
To prepare the squash, cut it in half crosswise. This means cutting through the center of the squash, only where it's hollow, rather than through the top and bottom where the stem is. Use a spoon to scoop out the seeds and stringy pieces in the center.
In the bowl of your slow cooker add a half cup of water. Then place the squash halves cut-side-down in the slow cooker. Cover the pot with a lid and cook on high heat for 2 hours, or low heat for up to 4 hours.
When the cooking cycle is complete, test the squash to see if it's done by piercing the outside with a fork. It should easily go through the skin when the squash is tender. Use oven mitts to remove the squash halves from the slow cooker. Then use a fork to pull the spaghetti-like strands out of each squash half.
Enjoy it warm as a side dish or save it to use in your favorite spaghetti squash recipe. We usually prepare this as a meal prep option to add to recipes during the week— spaghetti squash can be stored for up to 5 days in an airtight container in the fridge.
Notes
Nutrition information is for a quarter of a 3-pound spaghetti squash. This information is automatically calculated, so it's just an estimate and not a guarantee. Cooking Spaghetti Squash Whole: I had heard that spaghetti squash is easy to cook whole in a slow cooker, but I've tested that twice and both times the squash was miserably mushy inside. (No strands at all and very water!) My theory is that the squash steams itself when you cook it whole, so I don't recommend that method. When you slice into after cooking, so much water pours out! That's why I landed on this method, because the squash can release water directly into the slow cooker as it cooks, leaving you with perfectly tender strands.