Row 1: sc around.
Row 2: ::(ch4, 7 dc in 4th ch from hook, sl st in sc on previous row 3 stitches before base of this stitch, then cont with 8 dc in 4th chain from hook, sl st in in top sl st to form circle), sl st in 3nd sc in row 1, sc in each of next 15 (or as many as desired) sc:: repeat around
This stitch gets a little fiddly but I found that tacking the circle down on both sides gives it a nicer finish. I recommend making the first ch of the ch4 fairly long in order to be able to fit 15 stitches into it. After doing 7 dc, turn the half circle so the flat part is in line with the edge of the blanket and slip stitch into a stitch 3 (or 2) before on first row to tack it down on the right side. This is where having a longer first ch will help because when you are trying to get a dc into that first ch again it’s harder to access it since it’s now attached to the blanket. I sometime pull the half circle away from the blanket so I can see where the ch stitch is and can get my hook into it. After one or two more dc into it, it’s fairly easy to finish the rest of the 8 stitches.
I apologize for not explaining this better and will put up a video eventually.