How to Make It
With a mixer, beat butter and 1/2 cup sugar until fluffy. Add 4 eggs, one at a time, beating well after each addition. Stir in flour.
Spread batter evenly in a 9- by 13-inch pan.
Mix apricots with 1/2 cup sugar, cinnamon, and lemon juice. Arrange fruit, cut side up, in batter.
In a bowl, mix remaining sugar with cornstarch. Add sour cream, remaining eggs, and vanilla; beat until blended. Pour over apricots.
Bake in a 350° oven until cake surrounding apricots in the center is firm when gently pressed, about 1 hour and 20 minutes. Let cool at least 30 minutes; serve warm or cool.