A crostata is a flat, "free-form", rustic tart. It is sometimes called a galette. In the world of seasonal desserts, it is hard to imagine a dessert with more charm that can also be pulled together on short notice with a great deal of ease. Less fussy than a double crust fruit pie (a fruit pie has to "set up" for a few hours before it can be consumed, while a crostata only needs to sit for 20 minutes or so) and more elegant than a crisp (a crostata slices beautifully for serving), if you keep rounds of crostata dough in your freezer, you can easily prepare a fresh fruit crostata for an impromptu dessert with whatever fruit you find at the market.
In theory, if you can make the crust, a crostata is the easiest of desserts to make. Just roll out the crust, fill with fruit that has been sweetened to taste, fold the edges of the crust up and over the fruit and bake in a hot oven. In actual practice, fruit crostatas can be a bit tricky. When made with fruits that tend to be very juicy or that require a lot of sugar, the baking fruit can produce more sugary fruit juices than the casual crust can contain. Crostatas that experience a "blow out" in the oven are quite unattractive.
The main reason a small leak in the crust can create a minor disaster is that traditionally crostatas don't have any added thickener. The idea behind this is that the wide, open surface of the crostata should allow the fruit juices to evaporate and concentrate as the tart cooks, making a thickener unnecessary. Unfortunately, it doesn't always work this way. If the unthickened juices begin to escape, there is no stopping the flow. Because the fruit flavor without thickener is so pure and clean, for years I resisted adding any. But I have finally come to the conclusion that a small amount of cornstarch or flour is not the worst thing in the world. Certainly it is better than having a bottom crust that is soggy and gummy rather than crisp and flaky. It is also better than having all of your beautiful fruit juices flow out of the crust and into the pan (or worse yet, the floor of the oven) where they will burn.
Another less-than-traditional addition to my Strawberry-Rhubarb Crostata is the oatmeal streusel that I scatter over the surface of the fruit. Crostatas are frequently made with large chunks of fruit that maintain their shape as they bake and are beautiful to look at in the finished tart. Strawberries and rhubarb both collapse into a chunky compote as they bake. While not unattractive, it isn't particularly lovely, so covering up the fruit with a sweet and crunchy streusel adds (I especially like rhubarb with streusel) without taking away.
I love the strawberry-rhubarb version of this dessert. If you, or someone you know, loves the combination of strawberries and rhubarb, you should give this recipe a try. Apparently it is so good that it is irresistible. Several years ago while working at a private event facility I made miniature, individual-sized crostatas for a spring event. The party turned out to be smaller than expected and there were several tartlets left over. Since I happened to know that the husband of a friend and co-worker loved strawberry-rhubarb desserts, I sent two tarts home with my friend for the two of them to enjoy.
A week or two later I was having dinner with them when I decided to ask her husband how he had liked his strawberry-rhubarb crostata. My query was met with a puzzled look, accompanied by a "What strawberry-rhubarb crostata?". As I opened my mouth to reply, I received a sharp kick to the shins under the table. But it was too late. To this day I am occasionally reminded of what a big mouth I have as we laugh about the time my friend was unable to resist the call of the second tart as she drove home from work that day. Since she tells me that "they were so small....hardly big enough for one serving..." you should just make one large crostata. That way everyone will be able to cut as large a slice for themselves as they please.
1 recipe of Crostata/Galette Dough
3/4 lb. rhubarb, trimmed and sliced cross-wise into a 1/2-inch pieces
1 pint strawberries, washed and hulled and halved (quartered if large)
1/4 c. sugar
2 T. cornstarch
1/4 c. Strawberry preserves, well stirred
1 recipe Crumb Topping
On a lightly floured board, roll the dough into a 14-inch round about 1/8-inch thick. Place the round on a parchment lined cookie sheet (preferably without a rim). Chill the round of dough for at least 30 minutes.
When you are ready to build the crostata, place the fruit in a large bowl. In a small bowl, whisk together the sugar, cornstarch and a pinch of salt. Add the dry ingredients to the rhubarb and strawberries and toss to coat.
Spread the preserves over the chilled round of dough—leave about 3 inches of dough all around.
Top with the fruit mixture. Mound the crumb topping over the fruit.
Fold the edge of the dough up onto the fruit, pleating it attractively and pressing lightly as you go.
Place the crostata in a 450° oven either on the lowest rack or on a pizza stone. Bake for 10 minutes. Reduce the temperature to 400° and continue to bake until the crust is golden and cooked on the bottom and the fruit is bubbling. Slide the baked crostata (with the parchment) off onto a wire rack to cool—don’t do this if your cookie sheet has a rim. Let cool at least 20 minutes before serving. Serve with whipped cream or vanilla ice cream. This Crostata is best served the day it is made. Serves 6 to 8.
1 stick (4 oz.) unsalted butter, chilled and sliced 1/4-inch thick
1 c. plus 2 T. (4 1/2 oz.) all purpose flour
2 T. sugar
1/4 t. salt
2 T. ice water
Place flour and butter in a food processor and pulse/process until mixture is in little pieces. Turn butter and flour mixture into a large bowl and add the sugar and salt. Toss to combine. Drizzle the ice water over the flour mixture. Using your hands (or a fork), fluff the mixture until it begins to clump. If, when you squeeze some of the mixture it holds together, the dough is finished. Turn the dough out onto a counter and form into a mound. Using the heel of your hand, gradually push all of the dough away from you in short forward strokes, flattening out the lumps. Continue until all of the dough is flat. Using a bench scraper, scrape the dough off the counter, forming it into a single clump as you do. Form the finished dough into a thick disk. Chill for at least 30 minutes.
1/3 c. flour
6 T. packed brown sugar
pinch of salt
3 T. unsalted butter, chilled and cut into cubes
1/4 c. oatmeal
In a medium-sized bowl, combine the flour, sugar and salt. Rub in the butter until the mixture is crumbly. Add the oatmeal and toss to combine.