Coat an 8-inch-round disposable aluminum pan with cooking spray and sprinkle with flour. Bend sides of pan to form a heart shape.
Mix together cake mix, water, egg substitute and 1/3 cup of jam with an electric mixer on low speed for 30 seconds; change speed to high and mix for 2 minutes more.
Pour into prepared pan and bake until toothpick inserted in center comes out clean, about 30 minutes.
Cool on a wire rack for 10 minutes.
Invert onto a plate and remove from pan; place right side up on wire rack and allow to cool completely.
Meanwhile, melt chocolate in a double boiler over simmering water; allow to cool, then stir in remaining jam and half-and-half. Frost cake with chocolate mixture and outline perimeter of cake with raspberries.
(Note: If chocolate mixture stiffens while frosting cake, microwave for 30 seconds to soften.).