I have often wondered the same thing, I see napkins and hanky's with that as well and have reached the conclusion that one buys the pillow slip/napkin with the openwork on already and stitch out the design yourself.

sorry not a clue, welcome to cute.

I know in German it's "Hohlsaum". The dictionary says: hemstitch or Ajour-Stitch. But I don't know how it is done. :c(
Greetings from Hamburg, Germany
Magi

Hi! I believe that it is lace work called entredoux. It is sold in fabric stores or specialty stores. Then lace is woven through. Martha Pullen is a specialist in this art. Hope this helps.

That web site has pre-made items that you can purchase and then do your own decorating. I don't believe the average seamstress has a machine to do it at home.

If you're speaking about the tiny opework, it's done with a wing needle. The larger can be accomplished with carefully spaced small buttonholes.

Perhaps it can be done with a wing needle.

that is called an entredeaux stitch - and it does takes a wing needle to do it. I found something where it was discussed here previously - take a look at the answers

You also can purchase insertion entredeuax. It it stitched onto batiste strips, and has a "lip" on either side so it can be sewn onto both sides, with a tiny seam, and then the excess is trimmed away.

I just found this site: use the link and scroll down to faggoting stitch (klick the pic to enlarge).
Magi

Where in the UK are you? I'm going there Monday to visit my DD, SIL and my new grandson and I'd be willing to stash some entredeaux in my luggage and mail it to you once I get there. PM me with particulars and amount you might need. Cheers. *4u

Where are you in the UK it might make suggestions easier?

I've heard these trims referred to as "insertion lace" here in Australia, so I checked ebay uk for you and have a link to an auction for a similar lace (the one you weave ribbon through), browse around ebay and when you find one similar to the one you like, check online for a shop near you (in Australia that would be Spotlight etc)...those ebay prices are pretty good though.

If I was trying to replicate this cushion (which is seriously cute!), I'd embroider the centre panel and cut it to the size of my cushion/pillow then it looks like an insertion lace has been used to join a larger rectangle of plain white fabric, then another insertion lace, with a yellow ribbon woven through it (on 2nd look it seems there might be an even smaller yellow woven lace in the pillow too) and finished with a frill of Broderie Anglaise trim/lace. HTH :) xXx