Whisk together the unsweetened cocoa powder and granulated sugar in a medium saucepan.
Slowly pour in the whole milk and heavy cream while whisking until the mixture is smooth, about 1–2 minutes.
Heat the pan over medium heat, stirring constantly, until small bubbles form around the edges and steam rises, roughly 5 minutes.
Remove from heat and stir in the vanilla extract. Add blue gel food coloring drop by drop until the desired hue is reached.
Divide the cocoa between two mugs and serve immediately.
Notes
For a dairy-free version, substitute the whole milk and heavy cream with unsweetened oat milk.To maintain the vibrant blue hue after reheating, stir in an additional drop of gel coloring.
Nutrition
Serving: 1mugCalories: 200kcalCarbohydrates: 29g
Keyword blue hot cocoa, festive drink, Frostbite Blue Christmas Cocoa, holiday cocoa, winter beverage