Add cashews to a bowl and cover with filtered, room temperature water. Place in a shady spot on your counter. Soak at least 6 hours and up to 12, then drain and rinse.
In a high powered blender, combine cashews and all remaining ingredients, except alcohol. Blend until smooth and creamy.
Pour mixture into a saucepan and bring to a simmer. Simmer for 6-10 minutes, stirring every minute or so, until it has noticeably thickened. Watch carefully and adjust heat as necessary, so it doesn’t bubble over. The nog continues to thicken considerably in the fridge. Reheat in a saucepan with some water until warmed through.
I serve 1 cup of nog with 1 ounce of bourbon or alcohol of choice. Or refrigerate until chilled and serve.
Leftovers will keep tightly sealed in the fridge up to 5 days. I haven't tried freezing it!