preheat oven to 350 degrees F and line a cookie sheet with parchment paper
Melt butter in the microwave until very soft and almost completely melted. 30 seconds at a time.
In the bowl of a stand mixer beat together the sugars, vanilla and butter. Mix for 1 minute.
Add in the egg and mix until combined. Scrape down the sides of the bowl.
In a seperate bowl mix together flour, baking soda, and cornstarch.
Slowly add the dry ingredients into the wet ingredients. Mix until a dough forms.
Fold in the chocolate chips and Cadbury eggs.
Using a cookie scoop, form balls and place on your baking sheet.
Bake for 10-13 minutes depending on how done you like your cookies
Let cool on pan for 5 minutes and transfer to a wire rack.