The pattern looks complicated but is actually really easy. I love these mittens!

I used fingering instead of sports weight yarn.
Cast on 54 sts, which results in a nice tight fit around my arms without the mittens gliding off.
Knit the pattern only on the upper part of the mittens, on the bottom side there’s twisted ribbing. Started to increase sts when reaching the hand by knitting two sts out of one st.
Hand increase: + 7 ribs on the bottom side
Thumb increase: + 7 ribs on the thumb side
Thumb cast off: 7 ribs are cast off, cast on 4 sts in order to join palm and back of the hand section

Total rib count
Beginning: 27 ribs
Hand increase: 34 ribs
Thumb increase: 41 ribs
After thumb cast off: 35 ribs

After finishing the 10th pattern repeat, I didn’t start a new repeat but brought together the already existing last two ribs, that lie parallel to the apex, creating a three rib apex.
Cast off losely and formed finger holes by sewing palm and back section together.