I have made little pies several times, and they are universally acknowledged to be one of the cutest desserts.
(I got the idea from not martha, who is pretty fabulous).
I made this pie crust from Smitten Kitchen, and I used the top of a drinking glass to make tiny circles out of it. Then, I mixed two sliced apples with a tablespoon of sugar and a shake of cinnamon. (Yes, a "shake." Nothing too scientific about little pies). Finally, I used a cookie cutter to put a heart of pie crust on top.
Then, I baked them in muffin tins for about 25 minutes at 375, and I waited for the "Oohs" and "Aahs".