I made these chocolate Lego pieces to go on top of brownie cupcakes (that's fancy speak for brownies made in cupcake liners for easy transport) for my sister's wedding weekend. The brownies were the dessert at the rehearsal dinner, selected because my brother-in-law has always loved building with Legos and is now an engineer.
These are incredibly easy to make - I melted and colored white chocolate, then poured them into molds like these:
Once they are poured, the key to making them presentable is to lightly pick up and drop the mold onto the counter about one thousand times. This brings all of the air bubbles in the mold up to the surface and out of the piece. If you don't take this step, sometimes the air bubbles will take over and make your pieces look like something has been gnawing on them. I generally make several more than I will use so I can allow for error in terms of the air bubbles...no matter how careful I think I am, there are generally pieces that I decide to leave out like the one below. The more detailed the mold, the more air bubbles you will have to deal with. Almost every piece will have a small bubble here and there and I just go through the entire batch when they are all done and keep the best ones.
After the air bubbles are taken care of, I put the molds into the refrigerator to set up. These are thick pieces, so I left them alone for at least an hour. Then they just pop out of the molds and they're ready to use. I dusted these with an edible silver powder to add some shimmer since they were going on top of the brownies (Ben told me this was a horrible mistake because it made them look less like real Legos).