Set the crockpot on high heat and add the butter and olive oil. Slice the onions and fill the crockpot with them. Add a pinch of salt. Toss the onions to coat with the oils. Leave the lid OFF and walk away. I stirred the onions occasionally throughout the day, scraping the sides each time.
Total cooking time was approximately 8 hours, but that will vary for different slow cookers and crock-pots. When the onions are browned and soft to your liking, turn off the crock-pot. Serve warm or transfer to an airtight container and store in the refrigerator.
FREEZER TIP: Portion the onions into 1/2 cup portions and store aritight in a ziploc bag. Thaw in the refrigerator.
Caramelized Onions – In The Crockpot https://barefeetinthekitchen.com/caramelized-onions-in-crockpo/