Free-form pastries like this may not look quite as nice as an egg-washed lattice topped pie, but they involve far less effort, require no pie plate, and taste better. The first two benefits are pretty obvious, but the third is a little less intuitive, so let me explain. While a traditional pie is constrained to the volume of the plate you're using, a free-form pie is limited only by how high you can stack the fruit. Personally, I like to create a small mountain of fruit in the middle of the dough, leaving just enough crust around the edges to tuck some back over the edges. The second thing is that there's a trick to improving the texture of the bottom crust, while simultaneously making the crust easier to roll out and bake.
I roll the dough out on a layer of parchment paper on top of a layer of heavy duty aluminum foil. Since the dough won't stick to the parchment paper, you can get away with just a sprinkle of flour on top to keep the crust from sticking to the rolling pin. This not only means you can avoid incorporating too much flour, but that you can then bunch up the aluminum to create a "dish" that can go straight onto the oven rack. This ensures you get good heat transmission to the bottom of the pie, so that you get a crisp caramelized bottom crust instead of the sodden doughy mess that lies under most pies.
While we're on topic of crusts, I'm no expert, but here's what I've learned over the years about making a tender flaky crust. The most important thing is to avoid the formation of gluten chains in your dough. When mixed with water, the gluten in wheat flour forms long chains which is what gives some foods their chewy texture. While this great for breads and pastas, chewy is not an adjective I like to hear when it comes to pie crusts. To limit the development of gluten, there are couple things you can do. The first is to use very cold ingredients, which inhibits the development of gluten. That's why I usually keep a bag of flour and a stick of butter in the freezer. The second thing is to avoid over mixing as the more you mix a dough the more the gluten will develop.
This actually goes hand-in-hand with the technique for getting a flakey dough, which is to create layers of dough and uncombined butter. By using cold butter and not over mixing it, you'll end up with little specs of unmixed butter interspersed throughout your dough. When the crust is rolled out, these specs of butter flatten out, creating layers (i.e. flakes) of dough separated by layers of butter.
Lastly I like putting quite a bit of sugar into my crust. The main reason for this is that the crust (which is directly exposed to the heat of the oven), will reach temperatures high enough to caramelize the sugar. This not only creates it's own textural element, it also makes the crust taste amazing (think buttery caramel). The other reason is that I don't like adding a ton of sugar into the filling because it can overwhelm the flavor of the fruit. Most pies over-sweeten the filling, since it needs to sweeten the crust as well, but by adding sugar to the crust, you only have to add just enough sugar to the fruit to balance out its natural acidity.
Another great thing about these free-form pies is that they're perfect for when you have last minute brunch or dinner guests come over. The dough keeps in the freezer for weeks, so you can do a double batch of crust and keep the little pucks of dough handy. Even if you didn't have the foresight to prepare the dough (a predicament I often find myself in), it only takes about 10 minutes to make and another 10 minutes in the freezer to chill. Filled with some fruit you probably already have laying around, this makes for a fantastic last-minute dessert that you can start just before guests arrive and finish as they're eating their main course.
I really love the flavor that sits at the intersection of sweet aromatic white peaches, the bracing tartness of rhubarb, and the floral fragrance of vanilla, but you can really have a lot of fun with different combinations of fruit, cheese, herbs and spices. As we head into fall, how about an apple, grains of paradise and maple cream cheese pie; or a pear, cranberry and allspice pie? The only things you'll need to adjust are the amount of sugar and the amount of starch depending on the sweetness, acidity and water content of the fruit you use.
- To make the crust, add the flour, 2 tablespoons of sugar and salt to the work bowl of a food processor and pulse a few times to combine. Add the cold butter to the flour, scattering the cubes around, and pulse for 2 seconds at a time until the mixture forms small pebbles and there are no large clumps of butter remaining.
- Add the ice water and pulse a few more time until the mixture is still loose, but the individual pebbles are just starting to stick together (like damp sand). Turn the dough out onto a sheet of plastic wrap and use the wrap to press the dough together into a round puck about 1-inch (25mm) thick. Place in the freezer for at least 10 minutes, or you can keep it frozen for a few weeks until you need it.
- When you're ready to make the pie, put the oven rack in the middle position and preheat the oven to 400 degrees F (205 C).
- Place a piece of heavy duty aluminum foil on your work surface and then cover with a piece of parchment paper. If your dough has been in the freezer for a more than 10 minutes, take it out of the freezer a little ahead of time. You want it as cold as possible, but not so cold that you can't roll it out.
- Remove the pit from the peaches and slice into wedges. Add to a bowl along with the chopped rhubarb, remaining sugar and potato starch. Split the vanilla bean lengthwise and scrape out the seeds, adding them in with the peaches. Toss to distribute everything evenly.
- Roll out the dough into a circle about 1/6-inch (4mm) thick and then dump the fruit in the middle of the dough into a tall mound. Use the parchment paper to help you fold up the edges of the crust back over the fruit, forming some pleats along the way.
- Use the aluminum foil to form a shallow dish around the pie. Be careful not to tear a hole in the aluminum and leave enough room around the edges of the pie so the crust can breathe.
- Carefully transfer the pie to the oven, placing the foil directly on the oven rack. Bake for 25-30 minutes, or until the crust is golden brown.
- Serve hot out of the oven, or at room temperature with whipped cream or ice cream.