Preheat the oven to 180 degrees or gas mark 4.
In a pan on the hob, carefully melt the butter and the dark chocolate and mix together. Put to one side to cool.
Whisk together the eggs and the sugar until light and fluffy using an electric whisk or stand mixer.
Pour the chocolate mixture into the whisked eggs and sugar and fold.
Add your flour and cocoa powder and fold again.
Add a selection of the mini eggs, leaving some to one side for the top of the brownie.
Bake for 25-40 minutes, or until the middle no longer wobbles!
Once a cake tester comes out clean, top the brownie with the spare mini eggs and kit kat bunnies.
Leave to set for a couple of hours (it may eventually need to go into the fridge as the bunnies take a while to set!)
Cut into squares and serve.