Preheat oven to 170°C/340°F and arrange the baking rack onto the middle shelf.
Measure all the dry ingredients first, then sift them directly into a bowl.
Make a well in the center, and and add the beaten eggs, olive oil, and milk into the dry ingredients. Gently mix with a hand mixer for 5-10 seconds, until you have a smooth batter.
Grease and line an 8-inch cake tin, pour the batter, and bake for 25-30 minutes until risen and firm to the touch. Remove the chocolate cake from the oven, let it cool slightly then remove it from the tin and transfer it on a cooling rack to cool completely.
In a bowl, add the mascarpone cheese, orange zest, powdered sugar and cocoa powder. Mix with a hand mixer or a whisk until all the ingredients are combined. Spread the frosting over the cake, decorate with mini eggs, and serve.
This batter bakes up beautifully in an 8-inch round cake pan. It also works well as a 9x13-inch cake.
To make a 2-layer or 3-layer cake (as pictured) you'll need to adjust the quantities, and double or triple the ingredients.
To give your cake some extra mini egg flavor and texture, add 3-4 tablespoons of crushed mini eggs to the frosting.
Serve: You can leave your mini egg chocolate cake at room temperature for up to 2 hours.
Fridge: Cut the cake into slices and transfer them to a Ziplock bag or another airtight container to store in the fridge. They will keep well in the refrigerator for 2-3 days.
Freeze: Slice the leftover cake, store in freezer-friendly containers and freeze for up to 1 month. When you’re ready to serve, let it thaw in the fridge. Let it rest at room temperature for 20 minutes before serving.