Preheat oven to 350° F. Line an 8x8 pan with parchment paper and set aside.

In a small sauce pan, melt the butter on medium heat. Stir the butter continuously as the butter starts to bubble. There is a fine line between browning and burning butter, so keep a close eye on it and don't stop stirring! Also, don't turn the heat above medium heat. Darker flecks will start to form on the bottom of the pan, and the butter will quickly turn to an amber color. You'll know it's done when you can smell a nutty aroma. Immediately remove from heat and move to a heat-resistant bowl.

In a standing mixer, mix the brown butter and and sugar on high for 2-3 minutes. You'll want it to be smooth and not crumbly. Add egg and vanilla extract to the standing mixer and mix on medium speed until smooth. Add melted white chocolate and mix on medium speed until smoothu002du002dmake sure to scrape down the sides of the bowl so that everything is evenly mixed together.

In a separate bowl, whisk together flour, baking soda, cornstarch and salt. Add these dry ingredients to the standing mixer and stir slowly until just barely combined. Add Cadbury mini eggs and semi-sweet (or milk) chocolate chips and fold them into the dough.

Gently press the dough into the parchment-lined 8x8 pan. Press an additional handful of Cadbury mini eggs and chocolate chips into the top of the dough. Bake for about 25 minutes. Allow to cool for at least 15 minutes before cutting. Enjoy!