Preheat oven to 190C / GM 5 and line a baking tray with greaseproof paper
Cream the butter and sugar together until well combined
Beat in the egg and vanilla extract, a little at a time,
Stir in the flour until the mixture becomes a dough. Chill for a bit in the fridge if it's hot in your kitchen.
Lightly flour the work surface, roll out the dough to 1cm thick
Cut shapes out using a round cookie cutter and put each biscuit on the baking tray
Bake for 8-10 minutes until light golden brown, then set aside for 5 minutes to harden, then put on a wire rack to totally cool down.
To make the icing, put the icing sugar into a bowl, then add some of the water gradually, beating until smooth and fairly thick.
Divide into bowls of however many colours you are using. Add a few drops of colouring to each bowl and mix to colour the icing.
Put some into a piping bag with a very small round nozzle and pipe an outline 'wall' just inside the edge of the biscuits. Make sure it's a complete circle to avoid the flood icing escaping.
Thin out the remaining icing in the bowls with an extra teaspoon of water. This will be used for the flooding. You can either spoon on or pipe the runnier icing onto the biscuits inside the wall. Use a toothpick to smooth it over and fill in the gaps right up to the borders.
Once all the biscuits are iced, put them back on the baking tray and into the oven on as low as possible for up to 30 minutes to set the icing hard.
For the black 'holes' int he bowling balls either draw on using edible pen, or make some black thicker icing and pipe dots onto the icing. If you want the dots to be flat, add them with a bit of space between before the flooded icing is totally set.