Use a pushpin to make a hole inside the center top of each egg. To make it even bigger, use a skewer an twist until your hole is large enough to fit a piping tip.
Close up of skewer
Once piping tip or funnel is in place, pour whatever juice or liquid you'd like into the egg. I recommend pouring over a sink just in case you spill!
Once all eggs are a little less than full, place in egg carton, hole side up. Place straw or Popsicle stick in the hole and freeze overnight.
Take out of the freezer. The juice will have caused the eggs to expand, making it easy to pop the top of the egg off.
Hold it in your hand for a few seconds to melt it ever so slightly before pulling the top off.
Now just be sure to serve before they melt!