Take pan of baked brownies and crumble it up in a large bowl. You want your crumbs to be very crumbly and small, no large chunks.
Stir in chocolate buttercream. If the mixture looks dry or doesn't easily press together, add in more buttercream by the 1/4 cup until mixture very easily presses together.
Take 1 tablespoon of brownie mixture and roll onto a ball. I like to use a medium size cookie scoop because I like a 2 bite brownie truffle. Feel free to make these smaller. Don't make them much bigger or it will be hard to dip. Place the rolled balls on a parchment lined cookie sheet. It's ok if they are really close together but you don't want them touching each other.
Once the brownies are rolled and on your cookie sheet, transfer cookie sheet to the freezer for at least a 1/2 hour. At this stage of the process, if you don't have time to finish your truffles for the day, you can transfer the frozen balls to a freezer bag and dip them at a later date.
While your truffles are in the freezer, melt your melting chocolate. I like to melt mine in the microwave. To do this, place the melting chocolate in a microwave safe bowl. Melt chocolate in short, 15 second bursts, stirring between each burst. Stirring and short bursts of heat are very important to keep the chocolate from burning.
Pull the truffles out of the freezer. Using a fork to hold the ball, dip the ball into the chocolate. Slide the truffle coated in chocolate off the fork and onto a piece of parchment or wax paper to dry.
If you'd like to stripe your truffles, melt a small amount of white (or whatever color) melting chocolate and place in a piping bag. Snip just the very tip off and drizzle the white chocolate over the truffles. Wait until dry and enjoy!