Well, I tried an experiment tonight - took the grands biscuit dough, and chopped up an apple, mixed with some cinnamon and sugar. On one, I just flattened out the biscuit dough, and put the apple mixture in the center, though I did crimp the edges some. The others I put one flattened biscuit on the bottom, stuff in the middle, and another on top.

Verdict: failure for the two-biscuit version, as the dough in the center didn't cook, even after 16 minutes. The outsides were done, but not the middle. Scraped the apple out and ate that, and the edges, threw out the rest.

The one that I didn't put a "lid" on worked okay, but the edges didn't stay "crimped" - when I pulled them out of the oven, I put three thin slices of sharp cheddar on top, and it melted nicely onto the apples. That one was yummy, but not really worth doing again, next time I want an apple tart, I'll make a real one, but the biscuit dough was about to expire ... and it was worth a shot!