Did not like the afterthought thumb, so did these thumbs a-la-Alphamitts (linked above). These are not written for a small hand, so my other mods are below!

Notes:
Even for a ladies hand, and even in colorwork, 72 sts would be a big mitten for me…that’s what I would use for a sock in colorwork (my normal socks are on 64sts, size 1s, firm fabric).

Each girl, boy or heart in the chart is worked over 9 sts, so figure out what your cast on is for a mitten, then find your multiple of 9 and either increase or figure out what to do with extra stitches.

I prefer ribbing to a rolled hem, especially on kid mittens…keeps them on better…so that’s what I did. I knit my ribbing long enough to fold over, or unfold and tuck into a sleeve. :)

Mods:
Cast on 40, 2x2 for 36 rounds (to make a fold-up cuff, if desired).
1 round in pink, st st, adding in 1 stitch for start of thumb.
Start colorwork pattern, knitting first and last sts in pink on the front and back.
Start thumb increases (odd rounds) on round 3 of pattern, increase until there are 13 thumb stitches, put these on waste yarn after an even round.
Work 1 row of girl dolls, 1 row between, 1 row of hearts, 1 row between, 1 row girls, 1 row between, start center (ish) hearts.
Begin decreases on round 3 of center hearts.
Kitchener mitten top closed, 8+8 was my final count, I think.
9 rounds + decreases for thumbs.