Beware the Pi of March -- Blackberry Mini Pies

Happy Pi Day!  (3/14 = 3.14)  With a math professor in the family, we take Pi Day seriously here.  There has been a lot of baking & filling of pie shells here for the last few days, and I thought I'd pass along a few of our successes.

First up is the Mini Blackberry Pie you see before you with the holes cut to look like pi.  Heh.  Didn't see that one coming, did ya?

Made in tartlet pans, these mini pies are perfect for one, or could be shared by two.  They go together fairly quickly for what they are.  Unlike apple pies, berry pies don't need any peeling or chopping for the filling--just toss the berries in a little sugar, etc., and you are good to go.  I made them as one idea to give away to our children's math teachers.  Though I ended up doing something else altogether, the fact that they can stand to be out of the refrigerator for a while made them a good candidate.  If Pi day is being celebrated in your town, consider this recipe for the pies you hand to your children to bring to school. 

The recipe came from Martha Stewart, though it was passed down to me, so I am not sure what book or magazine it came from--but we should give credit where credit is due.  It's a great idea, but I did have one small quibble--there seems to be a low berry to crust ratio.  I grew up in berry country--a magical land where blackberries are weeds, so when I have berry pie, I want mine full to bursting with juicy goodness.  Since these mini pies were made in tartlet pans, there really wasn't a whole lot of room for bubbling, juicy berries.  So if you want the real deal, you better make yourself a real, full-sized berry pie.  (I'll blog about Marionberry pie later.)

A couple of tips:  First, the berry filling really does need to be heaped up as high as in the picture below to get a good fill.  The berries will cook down, I promise.  Second, wet your fingers in a little water and run them over the edges of the dough before trying to seal the top on.  You need a good seal to keep them from bursting apart during cooking.  And by the way, even if you make a good seal, there is a pretty good chance that juice will bubble out of the top regardless (5 of my six tartlets turned out this way), so be sure to set your tartlet pans on a big cookie sheet to catch the drips. 

Blackberry Mini Pies -- Yield:  6 tartlet sized pies

Pate Brisee
2 1/2 cups all-purpose flour
1 teaspoon salt
2 sticks (1 cup) unsalted butter, cold, cut into small pieces
1/4 cup ice water, plus more if needed

Mix together flour and salt.  Cut butter into the flour with a pastry cutter or with your fingers until the butter is in pea sized bits.  Slowly add the water, tossing the mixture with a fork (and adding additional water as needed) until the mixture clings together.  Press the mixture together in a ball and put it in the refrigerator to cool while you are making the filling.

Filling  & Finishing
20 ounces (5 cups) blackberries
3/4 cup sugar, plus more for sprinkling
2 tablespoons cornstarch
1/8 teaspoon salt
1 ounce (2 tablespoons) unsalted butter, cut into small pieces
1 large egg yolk
1 tablespoon heavy cream

 Preheat oven to 425 degrees. Gently toss blackberries with sugar, cornstarch, and salt in a large bowl.

On a floured surface, roll pate brisee to 1/8-inch thickness. Using a 5 1/2-inch biscuit cutter (I used a container lid the same size), cut out 6 rounds. Drape each round over a 4-inch fluted tart pan with a removable bottom, and press dough into bottom and up sides of pan. Edges will be flush with rims. Roll remaining dough to 1/8-inch thickness. Cut out 6 more 5 1/2-inch rounds.

Fill each tart pan with 3/4 cup blackberry mixture, mounding berries in the center. Dot berries with butter. Center 1 of the remaining dough rounds on top of 1 tart pan. Gently press top and bottom edges of dough together to seal (wetting the dough slightly will help get a better seal), and then pinch sealed edges. Repeat with remaining rounds. Transfer tartlet pans to a rimmed baking sheet, and freeze or refrigerate until firm, 15 to 20 minutes.

Lightly whisk yolk and heavy cream in a small bowl. Brush the top of each pie with egg wash, and sprinkle with sugar. Cut 4 vent holes in the top of each with a paring knife.   Bake for 30 minutes. Rotate baking sheet, and reduce heat to 375 degrees. Bake until berries are bubbling and crust is deep golden brown, about 30 minutes. Let pies cool in pans on a wire rack for 30 minutes. Unmold, and let pies cool completely on wire rack. Serve with whipped cream.