cacao nibs and chocolate coated amaranth balls (shaved chocolate, chocolate curls, or chocolate chips would work well too)
Process all filing ingredients in a food processor into a uniform mixture. Transfer into a parchment-lined rectangular container (I used my 12 x 4.5 " loaf pan, but anything of a similar size will do). Smooth out the mixture and press down with the back of a spoon or a spatula until the mixture is even and flat. Freeze for 1 hour.
Line a flat cookie sheet you can fit into your fridge or freezer with parchment and place the sheet in the freezer for about 5 mins while working on the next step (this will help the chocolate to set faster and not spread out on you too much in the next steps).
Melt your chocolate in a bowl and add remaining ingredients, stirring for a while until everything combines into a uniform mixture (the coconut oil helps to thin it out, so use more or less as needed).
Remove the frozen oat filling block from the freezer and transfer onto a cutting board. Cut into rectangles (or smaller squares if you prefer). Place a bar on a fork and dunk into the melted chocolate mixture to coat it. Wipe off any excess chocolate by running the bottom of the fork over the rim of the bowl. Place on the prepared chilled cookie sheet. Repeat with remaining bars. Sprinkle with toppings if using.
Place the cookie sheet in the fridge for about 30 mins to set, and enjoy! Keep bars refrigerated until use.