Warm the base: In a small saucepan, add the milk and cream.
Heat over medium-low until warm and steamy, not boiling.
Whisk in the cocoa and sugar: Sprinkle the cocoa powder and sugar over the warm mixture. Whisk steadily until smooth and no dry spots remain. If using chocolate chips, add them now and stir until melted.
Add coffee and vanilla: Stir in the brewed coffee or espresso, vanilla extract, and a pinch of salt.
Keep whisking until everything is fully combined and silky.
Simmer briefly: Let the mixture gently simmer for 1–2 minutes, stirring often. This helps dissolve the cocoa and meld flavors. Do not boil.
Taste and adjust: Add more sugar for sweetness, more cocoa for richness, or a splash more coffee for a stronger mocha vibe.
Cool and bottle: Remove from heat and let cool for 10–15 minutes.
Pour into a clean glass jar or bottle. Seal and refrigerate.
Shake before using: Natural separation may occur. Give it a quick shake and add 1–2 tablespoons to your coffee, or more to taste.