This cake must be assembled at least a day in advance so the corn bread can soak up all the fruit juices.
2 1/2 cups flour
1 1/2 cups cornmeal
4 teaspoons baking powder
1 teaspoon salt
1 1/2 cups sugar, divided
2 large eggs, beaten
2 cups nonfat milk
1/2 cup canola oil
1 cup creme de cassis (may substitute berry juice), divided
1 tablespoon powdered gelatin
10 cups mixed berries, such as blackberries, raspberries, blueberries or quartered strawberries
2 teaspoons freshly grated lemon zest (from 1 medium lemon)
3/4 cup raspberry jam
Confectioners' sugar, for dusting
Position an oven rack in oven's center; preheat oven to 400 F. Spray insides of 2 (8-inch) cake pans with nonstick cooking oil spray. Line pans with rounds of parchment paper, then spray paper.
Combine the flour, cornmeal, baking powder, salt and 1/2 cup of the sugar in a large mixing bowl. Add the eggs, milk and oil; mix until just combined. Pour batter into prepared pans. Bake for 20 minutes, until golden brown and a wooden toothpick inserted in center comes out clean. Transfer pans to a wire rack to cool.
When corn bread layers have cooled completely, invert, discard parchment paper and cut each layer horizontally to form 2 rounds (for a total of 4).
Have ready a 9-inch springform pan. Lay the first of 4 cornbread rounds in pan's bottom, cut-side up.
Cut second round of cornbread into rectangles or cubes. Use them to build an inner well for berries, standing them up close together along inside of springform pan (on top of bottom round of cornbread). They should come almost to top of springform pan.
Trim third round of cornbread so that it fits just inside well created by cornbread pieces, then set it aside while you prepare berries.
Place 1/2 cup of the cassis in a small bowl, then sprinkle the powdered gelatin over it; let it soften and set for 5 minutes.
Place remaining 1/2 cup cassis in a large saucepan over medium-high heat. Bring to a boil, then add cassis-gelatin mixture and stir until dissolved. Add the berries, lemon zest and remaining 1 cup sugar; mix to combine and cook for just a few minutes, long enough for berries to release their juices and begin to soften slightly. Remove from heat.
Use a slotted spoon to place half of berries in well created by cornbread-lined springform pan. Then press trimmed (third) round of cornbread on top of berries (it should be a tight fit) and spoon remaining berries onto that layer.
Place fourth round of cornbread on top, cut-side down, and press gently to make it even with pan's top.
Pour any remaining berry juice evenly over cake's top. Cover with plastic wrap, then put an empty cake pan on top and weigh it down with a 28-ounce can. Refrigerate overnight.
About 45 minutes before serving, bring jam to a boil in a small saucepan over medium-high heat, stirring to form a glaze. Remove from heat. Use an offset spatula to spread glaze over cake's top, leaving a half-inch margin around edge. Return cake to refrigerator and chill for 30 minutes.
To serve, remove sides of springform pan. Place cake on a platter and dust top with the confectioners' sugar.
Serve with sweetened whipped cream and/or lemon curd.
Makes 16 to 20 servings.