The Dutch heel incorporates additional circumference at the instep – but not as much as the standard heel flap for example – because the stitches of the heel flap are decreased and not short rowed (and therefor staying constant in stitch count). For example, a sock heel worked over 30 stitches on a 60 stitch sock has got nine stitches left after working a Dutch heel but 30 when working a standard flap heel. This means the instep of a flap heel is 15 stitches wide on each side but just nine stitches total on the Dutch heel.
Here is the schematic pattern for a Dutch heel for a 60 stitch sock. The heel is worked over 29 stitches.
Flap setup row 1 (RS): k29, turn work.
Flap setup row 2 (WS): sl1 wyf, p28.
Flap row 1 (RS): sl1 kw, k28, ktbl, turn work.
Flap row 2 (WS): sl1 wyf, p28.
Repeat flap rows 1-2 28 times more. You will have 15 chain sts at edge of heel flap.
Turn heel row 1 (RS): sl1 kw, k17, ssk, turn work.
Turn heel row 2 (WS): sl1 wyf, p7, p2tog, turn work.
Turn heel row 3-(RS): sl1 kw, k7, ssk, turn work.
Turn heel row 4 (WS): sl1 wyf, p7, p2tog, turn work.
Repeat turn heel rows 3 and 4 until all side sts are used up, 9 sts remain. (39 sts)
Work across 9 heel sts, then pick up and k 15 sts on RS of heel flap.
Work across instep sts keeping in pattern (stockinette), then pick up and k 15 sts down left side of heel flap. (69 sts)
Gusset setup: k9, k15 tbl, pm.
Gusset round 1: (work next row of main chart) two times, pm, k15 tbl, k24, slm.
Gusset round 2: (work next row of main chart) two times, slm, ssk, k to 2 sts before next marker, k2tog, slm.
Gusset round 3: (work next row of main chart) two times, slm, k to next marker, slm.
Repeat gusset rounds 2 and 3 until you have 60 sts total again.
It’s really square and the lines of the decreases on the bottom of the heel are quite dominant. But if you see this as a design feature, the Dutch heel is a nice one, especially if you don’t need a really large instep.