Preheat the oven to 180℃ fanbake (350℉), and line a 27.5cm x 17.5cm (11 x7 inches) pan.
Beat the softened butter and sugar until it is creamed and light in colour.
Add the jelly crystals (minus 1 tbsp needed for the icing) and beat well.
Next add the eggs one at a time. Making sure to scrape down the sides before each addition.
Gently fold in the flour and milk in alternate batches using the slowest speed on your mixer or beaters.
Pour in to your prepared pan and bake for 25 minutes (you can check the correct texture by touching the surface and the surface will spring back).
Allow to cool for ten minutes before removing the cake from the pan and cooling on a wire rack.
Once cool prepare the icing.