Whisk together the dairy free milk and coconut milk in a medium saucepan over medium-high heat and and bring to a gentle boil.
2 (13.5 ounce) cans unsweetened full fat coconut milk, 1 1/2 cups dairy free milk
While the milk is heating, whisk together the egg yolks and coconut sugar until combined in a large bowl.
6 large egg yolks, 1/2 cup granulated sugar
Pour a small amount of the warm milk into the egg mixture, whisking continuously. Repeat with more milk gradually until the milk mixture and egg mixture are combined. This is known as tempering, and slowly increases the temperature of the eggs so they don't curdle. Pour the eggnog back into the saucepan and add the cinnamon, nutmeg, salt, and vanilla. Heat over medium-low until it reaches a temperature of 160°F and the mixture coats the back of a spoon.
1/4 teaspoon cinnamon, 3/4 teaspoon fresh ground nutmeg, 1/2 teaspoon salt, 1 vanilla bean pod
Strain the dairy-free eggnog through a fine mesh sieve to remove any small bits of cooked egg that may have formed. Allow the eggnog to cool to room temperature. Transfer it to a pitcher, cover and refrigerate until chilled (2-3 hours) or overnight.
The eggnog will continue to thicken as it chills. Stir in more non-dairy milk until it reaches your desired consistency.
When you're ready to serve, dip the glass upside down in maple syrup, honey, or caramel then dip it into a mixture of cinnamon sugar. Spike with dark rum if desired and top with nutmeg.