Nonstick cooking spray
3/4 cup cake flour
1 teaspoon baking powder
1/2 teaspoon salt
5 large eggs, separated
1/2 cup granulated sugar
1 teaspoon vanilla extract, plus 1/4 teaspoon
2 tablespoons confectioners' sugar, plus 1/4 cup
2 cups heavy cream
1 1/2 cups strawberry jam
Fresh mint sprigs, for garnish