C/O 44 stitches. Divide onto needles 14/18/12
20 rounds/2.5 inches of 2 x 2 ribbing

Begin RT pattern:
On second needle:
rnd 1 p2, k2, p2, (RT, p2) 3 times
rnd 2, 3, 4 knit the knits and purl the purls

RT-- k2tog, then knit the first stitch again, then drop the stitches of the left-hand needle

Begin thumb gusset increases on round 1 of the third repeat of the RT pattern, working the increases every 3rd round until there are 14 stitches between markers, working in 2 x 2 ribbing as the stitches allow.

Knit one more round in pattern after the final increase.
On the next round, knit in pattern, but when you come to the gusset stitches, put them on a holder, cast on two stitches with backward loop cast-on. (Or do as I do and pick them up from the working yarn between the two columns of knit twos. This will give you a firmer edges for picking up the stitches for the thumb.)

Continue working the hand of the mitt until you have 9 twists total, then knit 6 rounds in plain 2 x 2 rib. Cast off. I use the sewn cast off. You can easily adjust this for the length you desire.

Put the thumb stitches back on needles, attach the working yarn and pick up and knit 4 stitches where you cast on the two stitches after putting the gusset on a holder. If you knit through the back loop to twist the stitches, you won’t have a big hole.

You are now at the beginning of the round, so knit in k2, p2 ribbing until you come to the 4 stitches you picked up. These will become a p2 in your ribbing pattern, so p2tog twice. Continue 2 x 2 rib for a total of 8 rounds (or however many rounds you need to get the fit you want) and cast off. Weave in the ends. You can use the tail of the working yarn where you began the thumb to close up any holes between the hand and thumb.

I used an entire ball (50 g) of Wool of the Andes and came up a little short. I needed just a few more yarns to work the second thumb. Fortunately, I had another ball of the same dye lot in my stash. I knew I was cutting it close, and I would have had enough yarn for the pair had I made the wrist cuff 18 rounds instead of 20. I’ll have to remember that when I start knitting up that lone ball of WotA in chocolate brown (and it’s not quite a full ball because I used a small amount of it in a hat. I might have to consider using a complimentary or contrasting color on the cuffs, LOL).