Size 10 double point needles
One ball of cheap chunky yarn or two balls of fancy chunky yarn (pictured above is fancy chunky yarn)
Chunky scrap yarn
Using 3 double pointed needles, cast on 26 stitches (8, 9, 9)
K1, P1 rib for 13 rows or until the cuff is as long as you desire
Round 14: K4, make 1 stitch in the front and back of next stitch (M1FB). Knit to last stitch on needle and M1FB again. K4 on the next needle and M1FB. Knit to end of needle. K4 on the third needle and M1FB. Knit to end of needle. You have increased the row by 4 stitches and should now have 30 stitches.
Knit 3 rounds
R18: M1, K1, M1, knit to end of round
All odd rounds: K one round
R20: M1, K3, M1, knit to end of round
R22: M1, K5, M1, knit to end of round
R24: M1, K7, M1, knit to end of round
R26: M1, K9, M1, knit to end of round
Knit 4 rounds
Transfer the first 11 stitches to a piece of scrap yarn.
Cast on one stitch. You should now have 30 stitches again.
Knit 6 rounds
K1, P1 rib for 4 rounds
Loosely bind off
Transfer the 11 stitches to two double pointed needles. With third needle, pick up and knit 4 stitches (make sure you leave at least a 6-inch tail of yarn). Knit one round. When you get back to the picked up stitches, K2tog twice, leaving you with 13 stitches total. Knit 5 rounds or till thumb is the length you prefer (you can try the mitt on at this point).
Bind off. Weave in tails. At the crotch of the thumb, use the extra tail to sew up any gaps.
Here is a pair I made with two kinds of worsted yarn knitted at the same time. They turned out really stiff and a little too big for my hands. They fit Stephen's perfectly, but they weren't his colors.
Here's some I made out of inexpensive Lion's Brand chunky yarn.