I got the recipe from the King Arthur Flour website, which I've found to be an excellent source in general. Made quite a few changes, mostly blandifying, but they still came out very well!
To start with the dough, where you really ought to: since I had no "Hi-Maize Fiber" or powdered cheese, my final recipe was
- about 2 cups of flour
- 1/4 tsp salt (not really, just a prolonged burst of salt-grinding)
- 3/4 cup cold butter
- a bit of grated Parmesan cheese, maybe 1/4 cup or a little less
After these were mixed reasonably well in my antique mixer, I added 6 Tbsp of coldish water (the tap would not oblige me with ice water) and mixed some more by hand. The resulting dough I divided and chilled as directed.
I made up the filling very simply: about 8oz. of mushrooms and about 8oz. of frozen spinach, sauteed in olive oil with a pinch of salt, marjoram, and coriander. You can see that this is less interesting than in the recipe, but I didn't have any cheddar (parmesan can be overpowering, so I didn't use it) nor an onion.
The rest I did as directed! And the end result was fabulous - the pastry flaky and buttery, the filling savory and delicious. I ate the one cut in half below, as well as the ugly and patched one. Five stars, would make again, etc.