Preheat the oven to gas mark 3 or 170 degrees.
In a large bowl, mix together the butter, sugar and golden syrup.
Add the egg, plain flour and baking powder and mix well until it forms a dough.
Using a rolling pin, crush the mini eggs in the packet so that they form small fragments.
Mix the mini eggs into the cookie dough ensuring they are spread throughout.
Form small balls of cookie dough (slightly smaller than golf balls), flatten and place on a lined baking tray. Leave space between each cookie as these will spread out in the oven.
Make sure fragments of the mini eggs are placed on the surface so that they show through after baking.
Bake for 15 minutes or until golden.
Leave to cool on the baking tray and enjoy.