How to "project" items above blocks in Minecraft?

I’ve been trying for a few days to figure out how to "project" items above blocks in Minecraft, similar to how a campfire works in the game. I’ve seen several mods that do this, but I can't seem to get it right. I want to create a cutting board in the style of Farmer's Delight. I think I can handle the rest of the code (determining which items can be cut and which cannot), but my only problem is how to make the item stay on top of the block. Could someone help me with this?