Make the whipped cream: Add the heavy cream to the bowl of a stand mixer. With the whisk attachment, mix on medium-high speed until the cream starts to thicken. Add the sugar, coffee & whiskey. Increase the speed to high & whip a few minutes until the cream gets as thick as you like it. Store in an airtight container in the fridge for a few days (if it lasts that long!)
Assemble sundaes: Add a few scoops of ice cream to chilled ice cream bowls or mason jars. Top with sauces, m&m’s, whipped cream & green sugar,