Preheat the oven to 350 F or 180 C. Line a 8×8 inch square baking pan with aluminum foil and then butter the foil.
In a small bowl, combine the flour, salt and cocoa. Set aside.
In a medium sized bowl, whisk together the eggs, sugars.
Trickle in the melted butter and vanilla, and continue to whisk.
Finally, stir in the flour mixture and spread ½ of the batter in the baking pan.
Evenly arrange the creme eggs on the batter, then completely cover eggs with reserved ½ of the batter. It may not be perfectly smooth.
Bake for 20-25 min or until a toothpick inserted in only the brownie part (make sure you don’t puncture the egg!) comes out clean. Let it cool completely.
While the brownies are cooling, make the fondant layer. Combine the butter, corn syrup and vanilla until the mixture resembles sweetened condensed milk.
Gradually add in the sugar.
Spread around ¾ of this mixture on the surface of the cooled brownie.
Dye the remaining ¼ cup of the mixture egg-yolk yellow and spoon dollops on the white part.
Run the back of a knife through the dollops to create a marble effect.
Chill the brownies for 2 hours before topping with ganache.
To make the ganache, heat the cream in either a saucepan or in the microwave until it boils.
Pour the cream over the chocolate and let it sit for 30 seconds before stirring.
Stir until smooth and pour over fondant layer, spreading with a spatula or knife.
Refrigerate till the ganache is set before cutting into squares.