Preheat oven to 180C/350F and grease and line an 8 x 8 inch square tin.

Place dark chocolate and butter into a heat proof bowl and place in the microwave, in 20 second increments, stirring in between until melted and smooth. Leave to one side.

Place eggs, sugar and vanilla extract into a large bowl and whisk until well combined and slightly frothy. Leave to one side.

Sift flour, cocoa powder, baking powder and salt together into a small bowl. Leave to one side.

Take your slightly cooled melted chocolate and pour into your sugar/egg mixture. Whisk until well combined and smooth.

Tip in your sifted flour mix and fold in gently with a spatula, just until the mixture is combined.

Place mini Creme Eggs into a Ziploc bag and beat with a rolling pin until you have Creme Egg rubble. Some large and small bits are fine.

Tip the Creme Egg rubble into your brownie mix and fold in gently.

Tip brownie mix into your greased and lined pan and smooth until level.

Place marshmallow fluff into a small bowl and microwave for 15 seconds (optional, but it makes it easier to work with!)

Spoon marshmallow fluff evenly over the brownies and then take a skewer and swirl the two mixtures together.

Slice your 4 full size Creme Eggs in half and place in the top of the brownies (I did 3 halves at the top and bottom and 2 in the middle, so 3 rows in total)

Place in the oven for 25-30 mins until risen and puffy. The edges will be done, but the middle will still be soft and pillowy, so at this stage turn the oven down to 160C and bake for a further 15-20 mins, until a skewer into the centre comes out with just a few solid crumbs.

Once baked, leave to cool in the pan completely.

Once cooled, transfer to a cutting board and slice into 9-12 bars.

Brownies will keep in an airtight container, at room temperature, for 4 days.