Simple Woolen Mittens
Plain mittens, knit in the round on dpns with a thumb gore (“sore thumb” style). Both mittens are knit the same (there is no left or right mitten).
When knit on US 7 needles the main part of the mitten was only 6.5” around, so you can get a smaller size by using one size smaller of needles. I wouldn’t recommend going up a size of needles, though, just because IMHO mittens should be densely stitched so as to avoid the cold and snow getting in.
The cuff and thumb gusset runs long, but people I’ve knit mittens for like this (avoids that gap between the end of your coat sleeve and the start of your mittens).
Even when knitting the smaller size (6.5” circumference), I still needed about 15 yards of yarn from a second hank to finish the second mitten. A single hank of the Hullabaloo would probably make a pair of mittens for a child; otherwise you’ll need 2 hanks to make a pair of mittens for an adult.