Place egg whites in a small bowl; let stand at room temperature for 30 minutes. Meanwhile, in a small saucepan, melt chocolate and butter over low heat, stirring constantly. Remove from the heat; cool slightly. Coat a 9-in. springform pan with cooking spray. Place pan on a baking sheet; set aside.
In a large bowl, beat egg yolks on high speed for 3 minutes or until light and fluffy. Gradually add 1/3 cup sugar and vanilla, beating until thick and lemon-colored. Beat in baby food and chocolate mixture.
Beat egg whites on medium speed until soft peaks form. Gradually beat in remaining (1/4 cup) sugar, 1 tablespoon at a time, on high until stiff glossy peaks form; fold into batter.
Pour into prepared pan and bake at 350° for 30-35 minutes or until a toothpick inserted near the center comes out with moist crumbs. Cool on a wire rack for 20 minutes. Carefully run a knife around edge of pan to loosen; remove sides of pan. Cool completely.
Sprinkle with cocoa and confectioners’ sugar. Refrigerate leftovers.