Place the chocolate chips or chopped chocolate bar into a heat resistant bowl (glass or metal) and set aside. In a saucepan over medium-high heat, warm the heavy whipping cream until it just starts to simmer. You do not want it to boil! When you see small bubbles starting to form around the edge and a soft simmer starting in the middle, you can remove from the heat. When it's reached this point, pour the cream into your bowl of chocolate, cover it with foil, and let it sit for ~2 minutes.
Whisk the chocolate and heavy cream mixture together until it’s uniform in consistency and there are no bits of chocolate left on your whisk. Cover the surface of the ganache with a piece of plastic wrap and refrigerate until the ganache is slightly chilled. I wait between 1 and 2 hours.
Use a stand mixer with the whisk attachment or a hand mixer to whip the ganache on medium-high speed just until it lightens in color and creates a peak (similar to the consistency of buttercream frosting), about 2-3 minutes. *Do not over whip, the ganache may curdle if you do
Immediately spread the whipped ganache on top of the cooled banana bread. Top with crushed candy pieces if you wish, slice and enjoy! Be sure to store leftovers in an airtight container in the fridge. It will stay fresh for 3-5 days.