Pre-heat oven to 180⁰C.
Grease and line a 20cm square cake tin.
Sieve flour and cocoa powder together into a bowl.
Put butter, plain chocolate and creme egg into a bowl over barely simmering water (don’t let the water touch) and melt together, stirring to mix.
Allow the mixture to cool for a few minutes.
Stir in beaten eggs, Muscovado sugar, flour, cocoa and milk chocolate chunks mixing well.
Spoon mixture into tin and level with a spatula.
Place mini creme eggs halves (yolk side up) on top at equally spaced intervals (4 x 4).
Place on the middle shelf of oven and bake for 27 – 30 mins.
Ready when a crust has formed, centre is lightly springy and mixture doesn’t wobble on shaking.
Allow to cool in tin for 15 minutes before transferring to a wire rack to cool.
Dust with a little icing sugar and cut into 16 squares.