1.Preheat oven to 180°C/350°F. Grease and line a deep 25cm (10-inch) heart-shaped cake pan.
2.Beat butter in a medium bowl with an electric mixer until changed to a paler colour. Sift flour and ¼ cup of the sugar together. Beat flour mixture and milk into the butter, in two batches, until just combined.
3.Beat eggs and egg whites in a small bowl with an electric mixer until thick and creamy. Gradually add remaining sugar, one tablespoon at a time, beating until sugar dissolves between additions. With motor operating on low speed, gradually pour egg mixture into flour mixture; beat until just combined.
4.Spread mixture into pan; bake 50 minutes. Stand cake 10 minutes; turn, top-side up, onto a wire rack to cool.
5.To make fluffy frosting, stir sugar and the water in a small saucepan over high heat, without boiling, until sugar is dissolved. Boil, uncovered, without stirring, about 5 minutes or until syrup reaches 116°C on a candy thermometer (syrup should be thick but not coloured). Remove from heat; allow bubbles to subside. Beat egg whites in a small bowl with an electric mixer until soft peaks form. While mixer is operating, add hot syrup in a thin stream; beat on high speed for about 10 minutes, or until mixture is thick and cool. Reserve 2 tablespoons of the frosting in a small bowl; tint this green. Tint remaining frosting pink.
6.Spread top and sides of cake with pink fluffy frosting; decorate cake with roses. Spoon green fluffy frosting into a small piping bag with a small plain nozzle; pipe leaves onto cake.
This recipe is gluten-free and nut-free. Make sure a grown-up helps with the hot syrup for the fluffy frosting. This cake can be baked in a deep 23cm (9-inch) square cake pan for about the same time as the heart-shaped cake.Note