How We Did It
Any sort of bowl will do; we make square ones, round ones, tall ones, short ones. If you use plastic then you won't have to worry about cracking your glass later. Use something that is a bit wider at the top than the bottom so you can get your lantern out of its container later.
The first thing we did was venture into the garden to find some wintry treasures... honeysuckle berries, rosehips, and bits of pine all make for lovely additions. We had some glittered rosehips downstairs that always add beauty to things like this, so we added in a few of those as well.
We filled our bowls about halfway or a little less with water; this will be the 'shelf' for our candles to sit upon. Then we placed in our pretty bits. It was could outside, so we left our bowls here on the patio to freeze overnight.
The next morning, we had our bottom layer! Oh, they were so pretty already! We brought them inside, and gathered a few more pretties.
Maddie put her narrow glass in the middle of her bowl (this will hold a spot for the candle to go),
and put in her berries and evergreen sprigs.
We filled up our bowls with water the rest of the way, and froze them again. If the glass wants to float a bit, just put pebbles or other weights in it to hold it into place while the lantern finishes freezing.
When they were solid, we brought them in, and put a bit of warm water in the glass, to release it from the surrounding ice. Then we ran water over the outside of the bowls to release our lanterns.