Melt the butter and chocolate together until the butter is completely melted. Remove from heat and whisk until the chocolate is completely melted and the mixture is smooth.
Whisk in the whiskey, vanilla, and powdered sugar.
Whisk in the eggs and egg yolk until completely smooth.
Add the remaining ingredients and stir to incorporate.
Divide between six 4-oz buttered ramekins. Place the ramekins on a baking sheet and cook for 10-12 minutes - the edges should be set but the center will still be soft (although not wet). Remove from the oven, let cool 1 minute before gently loosening edges with a knife and inverting the cakes onto individual plates. Top with powdered sugar.
Recipe by The Kitchen Paper at http://c02.ddd.mwp.accessdomain.com/spiced-molten-chocolate-cakes/