Preheat the oven to 180°C (160°C for fan assisted ovens)/Gas Mark 4. Line 2 x 12-hole muffin trays with paper cupcake cases.
In a mixing bowl, stir the cake mix, eggs, oil and water gently together, then whisk (by hand or electric mixer) for 2-3 minutes until smooth and creamy. Divide the mixture evenly between the cupcake cases. Bake both trays together in the oven for 18-22 minutes. Remove from the oven and transfer the cupcakes to a wire rack to cool completely.
Place 1¼ tubs of the icing in a bowl and beat in a little pink food colouring paste or gel to give a pale pink colour. Spread the cupcakes with the pink icing. Use a teaspoon to top each with a smaller swirl of the remaining uncoloured icing.
Spray the blades of a pair of kitchen scissors with the cooking oil spray and cut each marshmallow in half widthways through the thick middle, then cut each half in half again to make 4 bunny ear shapes from each marshmallow. Dip the cut side of each ‘ear’ into pink glimmer sugar to coat. Arrange 2 marshmallow ears on each cupcake.
Use the mini chocolate beans and chocolate strands to make bunny eyes, whiskers and a nose on each cupcake. Store any leftover cupcakes in an airtight container in the fridge for 2-3 days.