Heat the sugar in a heavy saucepan over medium heat while stirring. The sugar will form clumps as it melts before completely melting and turning golden/amber in color.
When fully melted remove from heat and quickly whisk in the cubed butter (the mixture will bubble up when you add it). Make sure the butter is fully incorporated before slowly adding the cream in a small stream. Pouring in the cream too quickly might cause the caramel to seize. Whisk briskly until fully incorporated and smooth.
Finally, stir in the vanilla and pour the sauce into a heat-safe glass measuring cup to finish cooling before assembling the cups.
To melt the Chocolate:
We will use a double boiler method to melt the chocolate. Fill a medium saucepan with about 2 inches of water in the bottom and bring to a boil over medium heat. Take a medium heat-safe bowl and place over the boiling water in the pot, making sure there is a gap between the bottom of the bowl and the boiling water. Place the chocolate wafers in the bowl over the pot and stir until the chocolate is completely melted.
To assemble the Cups:
Line 2 mini muffin tins with 18 mini foil-lined cupcake liners. Spoon about 1 teaspoon of the melted chocolate into each liner and use a spoon to draw the chocolate up the sides to coat evenly. You should use about ½ - ⅓ of the chocolate in this step. Place the tins in the freezer to harden for about 5 minutes.
Once the chocolate is hard, remove from the freezer and distribute the chopped macadamia nuts evenly into the 18 cups. Then, spoon about 1 -2 teaspoons of the cooled caramel into each cup. The caramel should cover the nuts completely. Place in the freezer for another 10 minutes to harden.
After the caramel is slightly hardened, take out of the freezer and top with the remaining melted chocolate and a little sprinkle of sea salt. Refrigerate the cups for about 1 hour to harden completely. Take out of the fridge about 5 minutes before serving for optimum texture.
Notes
* I use these Belcolade Premium Belgian Bittersweet Chocolate Wafers from Bulk Barn.