Gather all your ingredients and tools in front of you—this makes the process smooth and enjoyable.
Place the small saucepan over medium heat and add the butter, cinnamon, and whole cloves.
Gently stir the mixture with a wooden spoon or whisk until the butter melts completely and the spices become fragrant, about 3-4 minutes.
Pour in the dark rum, allowing it to warm with the butter and spices, and stir to combine everything smoothly.
Slowly add the hot water or apple cider, stirring constantly until the mixture is silky and well blended, with a gentle simmer and aromatic smell.
Taste the drink and, if desired, stir in honey or brown sugar to add sweetness. Adjust spice or citrus zest for brightness if needed.
Pour the hot buttered rum into mugs or heatproof glasses, and garnish with a cinnamon stick or citrus zest if you like.
Serve immediately while warm, enjoying the rich aroma and smooth, spiced flavor with each sip.