Step 1

Preheat oven to 350°F. Spray a 9-inch springform pan with cooking spray. Arrange apricot halves, skin side down, in bottom of pan.

Step 2

In a small bowl, whisk together flour, oats, baking powder, cinnamon and salt; set aside.

Step 3

In a medium bowl, beat egg whites until soft peaks form. Gradually beat in 1/3 cup of sugar, until whites are stiff and glossy; set aside.

Step 4

In a large bowl, beat eggs and remaining 1/3 cup of sugar until mixture is thick and pale yellow; stir in vanilla.

Step 5

Whisk 1/3 of egg-white mixture into whole-egg mixture, then fold in half of the dry ingredients. Fold in remaining whites and then remaining dry ingredients.

Step 6

Spoon batter into pan and smooth top with spatula. Bake until very brown and somewhat firm, about 35 to 40 minutes.

Step 7

Cool completely in pan before removing sides and inverting cake onto a serving plate. Slice into 8 pieces and serve. Yields 1 piece per serving.