adapted from Matt Bites
1 cup salted butter or margarine, softened
6 oz. cream cheese, softened
2 cups all-purpose flour
1/4 cup granulated sugar
In a stand mixer fitted with the paddle attachment, beat butter or margarine and cream cheese at medium speed until creamy. Gradually add flour and 1/4 cup of sugar. Mix until a soft dough forms.
Shape dough into a flat disk and cover with plastic wrap. Chill 15-20 minutes. Cut dough into thirds and wrap 1/3 in plastic wrap. return it to the refrigerator to chill.
On a well floured surface, knead remaining dough together. Roll dough with a floured rolling pin. Gently lay dough inside spring-form pan and press up the sides. Place dough-lined pan in the freezer and freeze until dough is stiff. Next, prepare the berry mixture.
Berry pie filling:
6 - 7 1/2 cups fresh berries or frozen berries thawed and patted dry. (I used blueberries, raspberries, blackberries and strawberries)
1 cup granulated sugar
1/4 cup plus 2 tbsp. cornstarch
In a large mixing bowl, stir together sugar and cornstarch. Remove 1/4 cup of this mixture and sprinkle over the bottom of the tart crust (be sure to return pan to the freezer).
Add berries to the remaining mixture and toss gently to coat. Remove tart crust from freezer and pour in berries. Return to freezer while you roll out the remaining 1/3 of reserved dough.
To finish:
1 egg mixed with 1 tbsp. water for egg wash
1-2 tablespoons turbinado sugar
Preheat oven to 375 degrees.
Roll remaining 1/3 dough portion on a well floured surface. Cut into strips with a pizza cutter or knife. Place dough strips on top the berry mixture forming a lattice and cut off excess with a knife.
Brush lattice top with egg wash and sprinkle with turbinado sugar. Bake for 15 minutes at 375, then reduce temperature to 350 degrees. Bake for 30 minutes longer, then place a piece of aluminum foil over the top of the tart to prevent over browning. Bake for 30 minutes longer. Remove from oven and let cool. Chill overnight. Run a knife around the edge of the crust before removing the spring-form ring. Slice and serve.
