Other than pie shapes, I also prepared for the feast of St. Egon by trying the orange and sorrel sauce from Early French Cookery (p. 211). I was kind of amazed to find sorrel at my regular web food store (we get home delivery occasionally for convenience). I used juice from both Seville oranges and regular, and the sauce was tangy but very good. I didn't buy sole since I thought it a bit expensive for at test run. We had it with fish for dinner the first day and the leftovers with chicken the day after. The recipe in the book is based on a brief note of what goes with which fish, and not a complete extant recipe. I'm not sure about the generous amount of butter in it given that it is a sauce for fish probably served on a fish day. Using for example olive oil would probably be equally tasty, but different. If using no fat to rounden the flavour I would probably have wanted some stock or cooking juices from the fish.
Unfortunately I was ill and didn't go to St. Egon, but the kitchen made the sauce anyway. I had promised to get sorrel, which I did and sent with a couple of friends. I was kind of sad to wave a box of sorrel plants off and just go back to bed myself. This time I asked my local store to get it since I realised that they carry the brand of fresh herbs that grows the sorrel and could probably order them for me.