|Prep time: 1 1/2 hours||Cooking time: 30 minutes||Total time: 2 hours|
As if by magic, this batter separates into a layer of cake on the top and a layer of pudding on the bottom, with berries throughout (it would be great with peaches, too). Serve room temperature or chilled with freshly whipped cream on top.
Heat oven to 325°. Grease the bottom and sides of an 8 or 9-inch baking dish or a deep dish pie plate.
Make the cake batter in a blender by combining the melted butter, buttermilk, ½ cup of the sugar, egg yolks, flour, and salt. Blend until smooth. Pour into a large mixing bowl and stir in the berries and lemon zest.
Beat the egg whites in a separate bowl until they form soft peaks. Sprinkle in the remaining sugar and beat again. Fold them into the batter until they are thoroughly combined.
Pour into the prepared baking dish. Find a pan large enough to hold the dish and add about ½-inch warm water, or enough to come within 1 inch from the top. Transfer to the oven and bake until the top is golden brown and the center is set but still jiggles, about 50 minutes.
Cool completely on a rack, and optionally chill in the refrigerator before serving with whipped cream.