This scrumptious, lightly spiked sundae is a fabulous mashup of Irish coffee and a brownie ice-cream sundae. We consider this dessert the best of both worlds.
Combine sugar with ¼ cup water in a medium saucepan. Bring to a boil over medium-high, cook until amber and just beginning to smoke, about 4 minutes. Remove from heat, carefully whisk in heavy cream, butter, and 1 teaspoon kosher salt. Stir in whiskey. Use immediately for sundaes. (Sauce can also be cooled and stored in an airtight container in the refrigerator for up to 1 month. Gently reheat before serving.)
Layer scoops of ice cream and crumbled brownies in each sundae glass. Top with Whiskey Caramel Sauce and softly whipped cream. Serve immediately.