Preheat the oven to 160°C (140°C fan forced). Grease a 2 litre ovenproof bowl (about 20cm across the top) with a little softened butter, then dust with flour. Lightly grease 3 muffin holes in a regular size muffin pan with butter.
Open the cake box, remove enclosed frosting sachet and reserve for another use. Mix the cake mix, eggs, butter and milk together gently in a medium bowl and whisk with electric mixer or low speed for 30 seconds then on medium speed for 2 minutes, until smooth and creamy.
Spoon some of the cake batter into the 3 greased muffin holes, filling to 2/3 full. Pour the remaining cake batter into the ovenproof bowl.
Place in the oven and bake the cupcakes for 18-22 minutes and the bowl for 55-65 minutes or until a skewer inserted into the centre comes out clean. Leave to cool for 10 minutes on a wire rack then remove the cakes from the muffin tin and bowl. Place rounded sides up on the wire rack and leave to cool completely, (about 1 hour for the large cake). Cut off the rounded tops from the cake and 2 of the muffins.
Spoon nearly all the frosting into a large bowl (reserve 2 tablespoons for the carrots) and beat in enough pink gel food colour to make a pale pink colour. Place the bowl cake on the cake board, cut side down and spread 1/2 of the frosting over the cake using a small palette knife. Use the frosting to adhere the cupcakes to the bowl cake for the feet and bunny tail. Use toothpicks to secure in place, if necessary. Place a marshmallow half, cut side down, on top of each cupcake ‘foot’ to resemble heels. Spread a thin layer of frosting over and around the cupcakes. Chill the cake for 30-45 minutes to set the frosting.
Spread nearly all the remaining frosting over the cake (reserve a little to spread on the cake board). Roll out the ready-to-roll icing on a surface lightly dusted with icing sugar. Use a rolling pin to roll out into a small circle about 3-4mm in thickness. Stamp 2 circles out with the larger cutter and 6 small circles out with the smaller cutter. Press the large circles into ovals and stick onto the bunny feet with the smaller rounds.
Sprinkle the whole cake liberally with 2/3 of the coconut and press gently into the frosting to make sure it stays in place. Shake the remaining coconut together with a little green gel food colour in a resealable food bag, until evenly tinted. Spread the remaining pink frosting on the cake board and cover with the green coconut, pressing it down gently.
Scatter the cookie crumbs in patches on the coconut ‘grass’ to resemble mud. Beat the reserved white frosting with a little orange gel food colour in a small bowl until evenly coloured. Spoon into a piping bag fitted with a plain nozzle. Pipe a few ‘carrots’ in the cookie mud. Just before serving the cake add the mint sprigs to resemble carrot tops.
Cut ears from the card and wrap the ends that will be inserted into cake with cling wrap. Insert into the cake. Remove the ears, cling film and toothpicks before serving. Store the cake loosely covered with cling wrap in a cool place for 2-3 days.