Heat almond milk, honey, and ginger in a saucepan over medium heat and let simmer for 5 minutes. Whisk in cashew butter and cocoa until dissolved, about 2 minutes. Reduce heat to medium-low and let stand to allow flavours to meld, 2 to 3 minutes.
Whisk in vanilla (if using), cinnamon and sea salt. Strain through fine sieve into two mugs and serve with grated dark chocolate.
Notes
Tip: Turn this into a summer drink by letting it cool, then pouring it into a shaker with a few ice cubes and a scoop of chocolate ice cream. Shake and pour into pre-chilled glasses.