Easter Mini Egg Traybake Cake

Preheat the oven to 180°C (160° fan/ 350℉/ Gas 4) and line a 20 x 30cm (9x13-inch) traybake tin with baking paper.
Cream together the softened butter and sugars until light and fluffy. You can use a wooden spoon or an electric mixer.
225 g Unsalted Butter, 200 g Caster Sugar (superfine), 25 g Light Brown Sugar
Beat in the eggs one at a time and mix in the vanilla extract.
4 Large Eggs, 1 teaspoon Vanilla Extract
Fold in the flour and crushed mini eggs. Make sure the mini eggs are crushed into very small pieces otherwise they will sink to the bottom of the cake.
225 g Self Raising Flour, 100 g Mini Eggs
Spoon the cake batter into the prepared tin and bake for 30-35 minutes until golden brown. Set aside to cool.
To make the buttercream frosting, mix together the sieved icing sugar, softened butter, vanilla extract, and milk with an electric whisk until smooth and creamy. If the mixture is still a bit stiff, add a touch more milk.
200 g Salted Butter, 400 g Icing Sugar (powdered sugar), 1 teaspoon Vanilla Extract, 1 tablespoon Milk
Remove the cooled cake from the tin then spread the top of the cake with the smooth vanilla buttercream. I use a palette knife.
Sprinkle the top with the mini eggs before cutting it into slices.
196 g Mini Eggs