How to Make It
Prepare the Filling: Combine berries, sugar, cornstarch, zest, and juice in a saucepan over medium-high; bring to a boil. Reduce heat to medium-low, and simmer, mashing berries as they cook, until thick and bubbly, about 10 minutes. Cool completely, about 30 minutes.
Prepare the Crust: Stir together flour, pecans, baking powder, and salt in a medium bowl.
Combine sugar, butter, and shortening in a large bowl, and beat with an electric mixer on medium speed until light and fluffy, 2 to 3 minutes. Add egg and vanilla, beating until combined. Gradually add cream, beating on low speed until incorporated.
Add flour mixture to butter mixture; beat at low speed until well combined. Divide dough in half; place each half on a piece of plastic wrap. Shape each half into a 6- x 4-inch rectangle, about 1 inch thick. Wrap, and freeze 2 hours.
Prepare the Topping: Preheat oven to 350°F. Whisk together flour, granulated sugar, brown sugar, and salt in a medium bowl. Using a pastry blender or two knives, cut butter into mixture until it resembles small pebbles. Chill until ready to use.
Using a box grater or a food processor fitted with a grating blade, grate half of the dough (leave remaining half in freezer). Press grated dough into bottom of a 9-inch square pan coated with cooking spray. Bake in preheated oven until beginning to brown around edges, 12 to 14 minutes.
Remove pan from oven. Carefully spread Filling over Crust, from edge to edge. Grate remaining half of dough, and sprinkle over Filling; gently press. Sprinkle Topping over dough. Bake in preheated oven until well browned, 35 to 40 minutes.
Cool completely on wire rack, about 2 hours. Cut into 12 bars.