In a small saucepan, combine the whole milk, cream, molasses, and spices over low heat. You want to barely bring this mixture to a simmer without boiling it.
Once your mixture is heated through, remove it from the heat and cover it. Allow it to steep for about 20 minutes so all those delightful spices can infuse their flavors into the milk and cream.
After steeping, strain out the solids like cloves and ginger slices, discarding them afterward. Return the liquid back to low heat and gently reheat it before adding in your cocoa powder and chopped chocolate.
Once you've added the cocoa and chopped chocolate, whisk vigorously until everything is fully melted and combined into a thick, smooth consistency.
Pour your warming concoction into mugs and top generously with whipped cream or vegan marshmallows—or both if you're feeling indulgent!