For Crust:
1/2 cup all-purpose flour
3/4 cup yellow cornmeal
6 tablespoons confectioners sugar
1/2 teaspoon salt
1 stick cold unsalted butter, cut into pieces
For filling:
3 large eggs
1/2 cup granulated sugar
1 1/2 tablespoons all-purpose flour
1/2 teaspoon finely grated lemon zest
1/2 teaspoon finely grated lime zest
1 tablespoon fresh lemon juice
1 tablespoon fresh lime juice
2 tablespoons whole milk
2 cups blueberries (10 oz.)
3 tablespoons apricot jam, heated and strained
Preheat oven to 375 degrees F. Line a buttered 8-inch glass baking dish with 2 (18-by-6-inch) sheets of foil, overlapping them in opposigte directions so that there is overhang on all 4 sides.
Pulse together flour, cornmeal, confectioners sugar, salt and butter in a food processor until mixture resembles coarse meal. Press onto bottom of baking dish and 1 inch up sides. Bake in middle of oven until golden brown, about 20 minutes.
Whisk together eggs, sugar, flour, and zests. Whisk in juices, milk, and a pinch of salt. Toss blueberries with jam in another bowl.
Whisk egg mixture and immediately pour into hot crust, then bake until just set, about 17 minutes. Gently spoon berries evenly over top and bake 2 more minutes more. Transfer baking dish to a rack and cool.
Chill, covered, overnight (8 hours). Use foil to lift dessert out of dish, then cut into squares