Stir together the balsamic vinegar and honey until the honey is completely dissolved.
In a bowl cream together the butter, salt, fresh thyme and garlic until combined.
Add the balsamic mixture and start to mix on low speed to begin incorporating the vinegar into the butter.
Increase the speed as the mixture comes together more, finally mixing on high speed until combined and creamy.
Immediately put the compound butter into a piping bag or gallon plastic bag.
Snip off the corner and pipe into a silicon ice cube tray.
Tap the tray on the counter, then place in the refrigerator for at least 4-6 hours to harden.