To warm coffee cups, fill with almost boiling hot water.
Whip the cream until thick, but not stiff; it should still be able to run off of a spoon.
Pour the warm water out of the coffee mugs. Fill 3/4 full with coffee, add the brown sugar and stir til dissolved.
Add the whiskey and stir to combine.
Hold a spoon upside down over the coffee and gently pour the cream over the back of the spoon, allowing it to gently pool on top of the coffee; filling to the top of the mug. Do not stir; sip and enjoy!