Put the ingredients into your food processor and run until thoroughly mixed. You don't have to worry about flakiness or graininess or anything like that. Just get it mixed. It's fine if the butter is soft. Then you can chill it if you'd rather not have to flour your fingers for each tartlet, or just go ahead with it as is. Use your fingers to press a 1/2-ounce ball of dough into each mini-tart cup. Using that amount of dough per tartlet should give you 24, which is the standard amount per pan and the yield given for this recipe. It's really better, though, if the dough is very thin. So . . . if you really want to be obsessive about it, and you have a scale (which I do), then 3/8 of an ounce is better. But as I often say, Don't drive yourself crazy! The world won't come to an end if the dough is a little thick.

Combine the egg, brown sugar, butter, vanilla extract and pecans in a medium bowl until well mixed. Fill each dough shell no more than 2/3 full. (Be sure NOT to overfill, as the filling will bubble up over the edges and make a fine mess. You will have some filling left over, so if you're making multiple batches don't make the same amount of filling as you make of dough until you see how much you need. I tend to make this mistake because I don’t want them to be skimpy, but it’s much better to just be restrained.) Bake for 25 minutes or until the tops are golden. Transfer the pans to a wire rack to cool for at least 10 minutes, then run a sharp knife around the outside edges of the tassies to release them from the pans.