blackberry lemon pudding cake

i found this a few years ago in cooking light, and it's been one of my favorites. so when i saw some delicious blackberries for sale at costco, i had to make it. it takes a while for the cake to settle, so give it about 45 minutes to cool.

1/4 c. all-purpose flour
2/3 c. sugar
1/8 t. salt
1/8 t. nutmeg
1 c. buttermilk
1 t. grated lemon rind
1/4 c. fresh lemon juice
2 T. butter
2 large egg yolks
3 large egg whites
1/4 c. sugar
1 1/2 c. blackberries

preheat oven to 350°.

lightly spoon flour into a dry measuring cup; level with a knife. combine flour, 2/3 c. granulated sugar, salt, and nutmeg in a large bowl; add buttermilk, rind, juice, butter, and egg yolks, stirring with a whisk until smooth.

beat egg whites at high speed of a mixer until foamy. add 1/4 c. granulated sugar, 1 T. at a time, beating until stiff peaks form. gently stir one-fourth of egg white mixture into buttermilk mixture; gently fold in remaining egg white mixture. fold in blackberries.

pour batter into an 8-inch square baking pan coated with cooking spray. place in a larger baking pan; add hot water to larger pan to depth of 1 inch. bake at 350° for 35 minutes or until cake springs back when touched lightly in center.