Chop the chocolate into small pieces using a large sharp knife and a large cutting board. Place the chocolate into a medium bowl and set aside.
Measure out the heavy cream and pour it into a microwave safe bowl (or use a microwave safe measuring cup). Measure the butter and place it in the cream. Microwave on high for 30 seconds, until very warm but not boiling. Pour the cream mixture over the chocolate and let sit for 5 to 7 minutes.
Take a whisk and whisk together the cream and chocolate. If the chocolate hasn’t melted all the way, put it in the microwave for 15 seconds, then stir again. If needed, heat another 15 seconds in the microwave and stir until no lumps remain.
Add the triple sec and vanilla extract into the bowl, then stir with the whisk until fully combined. The chocolate mixture should be thin and glossy. Stick the bowl in the refrigerator to chill for 1.5 to 2 hours.
Before you remove the bowl from the fridge, prep the topping ingredients. Get out your toppings and small plates to put them on. If using hazelnuts, chop them up very fine in a food processor (or with a large sharp knife and cutting board). If using coconut flakes, run them through a food processor to make them more fine. The cacao powder can be put straight into a dish.
Place a piece or parchment or wax paper on a sheet pan (or other large flat surface) and set aside.
After the allotted time, take the bowl of chocolate mixture out and touch the chocolate. It should be firmed up but still soft and slightly tacky to the touch.
Next you’ll scoop the chocolate into roughly 1 inch balls. Use a melon baller (or a measuring spoon for ½ tablespoon) and scoop out some chocolate. Take a spoon and dig the chocolate out of the melon baller with the spoon. Next use your fingers to round the ball on the spoon as best you can before taking it off the spoon to finish rounding and smoothing with your fingers.
Take the chocolate ball and place it in one of the plate of toppings. Carefully roll it around with your fingers, then place the finished truffle on the parchment paper. Repeat, using the different toppings, until the chocolate mixture is gone.