Preheat oven to 350 F and line a 9x9 baking pan with butter or parchment paper.
In a large bowl, add in your eggs and vanilla. Mix until well combined.
Next, add in your melted unsalted butter and brown sugar. Mix until well combined.
Add your flour, baking powder and salt to your large bowl and stir until everything is properly incorporated.
Lastly, slight crush your Cadbury Mini Eggs and add into the mixture. Do not over mix! Leave a little to sprinkle on top.
Pour the batter into your baking pan and bake for 30-40 minutes or until the edges are golden brown and the middle is fully cooked.
Allow 15 minutes to cool, cut and serve.