Preheat your oven to 180C / 350F / Gas mark 4 and line an 8x8 inch (20cm) tin with baking parchment.
In a medium sized mixing bowl mix the flour, cocoa powder and both sugars together.
Add in the vanilla, vegetable oil and the 3 eggs and with a gentle hand mix everything together.
Take your 3 cadburys cream eggs and cut them up into small chunks and gently mix them into the batter.
Pour the batter into your prepared tin and bake for 20 to 25 minutes.
If you like your brownies on the fudgy side they should be ready at 20 minutes, still check by inserting a pick into them and see how clean it comes out. If you like them a little more like cake give them a further 5 minutes.
Take them out of the oven and allow them to fully cool down in their tin. Once cool take the brownie out and cut into 12 squares.
If using crack open your remaining 3 cream eggs and place on top for decoration.
Kept in an airtight tin at room temperature these brownies will last 5 days.