Note: Standing double crochet (US terminology). Standing treble crochet (UK terminology). I will be describing this using the US terminology.
This stitch seems to have a few names, depending upon who you ask. I have heard it called a starting double crochet stitch. A standng double crochet and a chainless double crochet. No doubt someone will enlighten me on the differences at some point, but the reason for this post is to describe how I do this. I choose to refer to it as a standing double crochet. There are numerous ways to create a standing double crochet stitch. The method described here is my preference.
Chains at the beginning of rows/rounds can produce a messy, uneven appearance. This helps to prevent this.
Step 1: Pull up the loop on your hook to the height of a normal double crochet.
Step 2: Twist the hook in a counterclockwise direction,down towards you, wrapping the lengthened loop around your hook. You now have the original loop around your hook as well as an extra double strand Yarn over and pull through the extra double loop on the hook.
Step 3: 2 loops remaining on the hook.
Step 4: Yarn over and pull through the remaining 2 loops on the hook.