To make Toffee: Place butter and brown sugar in a small skillet, heat on stove on medium to low heat. Mix well with a wooden spatula, bring to a boil, make sure sugar has melted about 2-3 minutes. Remove from heat and add heavy cream, vanilla, a pinch of salt and bourbon. Mix well and return heat, and allow mixture to boil, decrease heat if needed. Make sure to continue to mix occasionally, about 5 minutes. Pour cooked toffee in a bowl with lid, allow to sit until completely cool and ready to be used.