Preheat the oven to 180C / 160C fan-forced. Grease and line a 20cm square tin with baking paper, ensuring two sides overhang.
In a large mixing bowl, beat the butter and sugars with an electric mixer until combined. Add the vanilla and egg and continue to beat until creamy. Sift in the flour and baking soda and stir until a soft cookie dough forms.
Add the chocolate chips and half the Easter eggs and stir. Press the cookie dough into your tin and spread out as evenly as possible. Press the rest of the Easter eggs on top.
Bake in the oven for 18-20 minutes or until golden brown. Leave to cool completely. Cut into bars and serve.