Just one. Something of a work in progress. It would probably work better to make a larger batch then put the excess in the fridge for future use.
North American flour is assumed; flour from other regions may need a different percentage water.
Mix and knead a little until just formed. Let sit covered on the kitchen counter until doubled, probably five to seven hours in a cooler (less than 70F) kitchen. This also depends on the amount of yeast and the starting temperature of the water, which I need to get under better control. Dough this small may have trouble getting going; maybe insulate the container from the counter if that is cold?
Flour a surface and roll out the dough into a rough circle with a rolling pin. Pretty flat but not super flat. Fill with suitable fillings; use damp fingers to wet the edges and close the dough over the filling. The filling probably should not have too much moisture in it, unless you like boiling hot liquid leaking out from the bottom and burning your fingers. Or I don't know, use a napkin?
Cook for 400F for 15 minutes or so. If you have a small dutch oven or similar oven-worthy pot (or you can cover it in heavy tinfoil, but that wastes tinfoil) preheat the oven and the dutch oven to 475F, cook for 15 minutes covered, then maybe five more minutes uncovered. This may or may not set off the fire alarm, maybe run the oven hood if you have one of those. Without the preheat of the dutch oven the cooking time is longer.
If the dough is sticky or thin it may be difficult to remove the calzone from the breadboard—you put it on a breadboard, right? In this case one idea is to place your hand on the calzone, invert the breadboard, and let gravity as slowed down by your hand remove the calzone from the breadboard. Using a spatula is a bad idea as that generally tears the dough under the calzone.
A calzone filling.
Cut grape tomatoes in half, sprinkle with not much salt, and cook or dry until pretty well shriveled up. Grate ginger, mash together with the dried tomatoes and well-drained sardines. Use as filling for the calzone.
The grape tomatoes can probably be replaced with capers.
In theory you could cook a hamburger, except as a calzone. Maybe sear the meat to brown it first, then top with cheese and pickles? Haven't tried this yet.
Trim off the bad bits and cut brussel sprouts in half. Steam the sprouts until just tender. Dice the sprouts, saute them in some olive oil (mostly to rid them of any excess moisture from the steaming), and use that for the calzone filling, plus the caraway seeds. Probably needed a bit of vinegar or grated ginger? But limiting the number of ingredients can also be a good thing to do.