That's pretty much the recipe I was using - and I *did* dust with semolina flour; it still stuck.

As for technique, as I explained to Janet, I *was* pressing against the counter - what I meant was that I was cupping my hand around the filling as I pressed down on the counter. I'm not an idiot, I know not to pick it up and cup it. Sealing it was the easy part; I have a lot of experience making filled cookies and pastries, so the seal was no problem - all of the ones I managed to make stayed sealed with no trouble.

Thank you for all your advice!