Pie crust can be a finicky creature. Even if you follow all the rules when making it—use cold ingredients; handle it gently; bake it at the right temperature—every now and then you'll wind up with a crack in your crust when it comes out of the oven. You can patch it with a bit of dough, but what if you've already tossed your dough scraps? Don't toss it—or worse, fill it anyway and wind up with a sticky mess. Pastry chef Emily Luchetti has a smart trick for patching the cracks with just a little extra flour and water.