This pattern came into being because for years I’ve wanted to make mittens & hats for my kids and grandkids that were warm enough to hold up to Wisconsin winters. While I could knit or crochet double layered mittens or hats, where the inside and outside were constructed separately, that isn’t ideal when trying to get a toddler to put their item on or off without the inside layer becoming misaligned with the outside layer. I wanted the inside & outside layers to be constructed together. I wanted the mitts and hats to be warm, and I wanted to be able to get a them done relatively quickly. The thermal crochet stitch seemed perfect, except it was primarily back and forth. I wanted something in the round. So I set out to make that happen.
You will need worsted weight yarn. A little lighter, or a little heavier will also do fine. Scraps work great for what I like to call “Monster Mittens” and "Monster Hats". I like to use wool or alpaca for warmth and make the size a little big for the wearer, so that I can wash and dry the final mittens to felt them a bit, which will make them more water resistant.
For your first time, I suggest a solid, tonal, or lightly patterned yarn, otherwise it can be a little hard to tell where you need to be making stitches.
I have a pretty roughly edited video available that walks through the pattern in one size. Even though it’s kind of choppy, it is helpful for transition areas and for those that are new to this type of construction. Here is the video link: https://youtu.be/-MLgKDC7Zoc