The Opal self-striped sock yarn I used will also make a pair of matching "big sister socks" (half done already, as you can see in the above photo). If you are familiar with knitting and Opal's "Sock Philosophy" these baby sockies are an easy adaptation and knit up quick.
Use a size 3 (US) needle and Opal self-striping sock yarn.
Cast on 36 stitches -- 12 per needle on 3 needles. (12/12/12)
Rib knit (k2, p2) for about an inch and a half.
Knit 3 rounds in stocking knit.
In the next round begin buttonholes (by casting off) -- 6 total holes-- 2 per needle -- 3 stitches each at end of round each needle should look like this IIxxxIIxxxII (I = stitch x-cast off stitch)
In the next round finish the buttonholes by casting on the missing stitches as you knit the round.
You should have 36 stitches again.
Knit a couple more rounds as desired and split for heel flap. Two needles for instep should have 9 stitches each. Heel flap (all on one needle) should have 18. (9/9/18)
Work heel flap (roughly square).
Turn heel: k9, k2t, k1, turn, s1,p1, p2t, p1, turn, s1...and so on. End on knit row.
Pick up 10 on gussets.
Begin reduction: Reduce at heel as normal AND reduce at sides of instep also (-4 per reduction)
Alternate rounds plain knit, then reduction until you have reduced to 24 stitches remaining.
Knit 3 rounds plain stocking knit.
Split for toe -- keep 6 stitches on each top needle and 12 stitches on bottom. (6/6/12).
Reduce toe until only 8 stitches remain (2/2/4) -- last knit round put onto 2 needles (4/4).
Finish with the Kitchener stitch.
Run a narrow grosgrain ribbon through the button holes, turn down the cuff, and there you have it.
Note to beginning knitters: If you've never knit socks before, baby socks are a great place to start. But these Sockie instructions are incomplete, abbreviated for those familiar with sock knitting. For a first attempt at baby socks I recommend the very thoroughly explained North Country Baby Sock pattern.