Preheat oven to 375.
Add the granulated sugar, brown sugar, and kosher salt to the bowl with the butter and whisk well. Let sit for three minutes before whisking again. Repeat one more time.
Add the eggs and vanilla. Whisk well to combine and continue whisking until the mixture is lightened and thick. Set aside.
Weigh the all purpose flour into a bowl. Add malted milk, baking powder, and baking soda. Whisk well.
Mix the dry ingredients into the wet ingredients with a spatula, being careful not to overman. Add half of the white chocolate, dark chocolate, and mini Cadbury eggs. Fold together.
Place dough in the refrigerator and chill for at least a half an hour.
Scoop dough using a #30 (1.22 oz.) cookie scoop about two inches apart onto a parchment lined baking sheet. Cover the tops of the dough balls with remaining chopped chocolate and eggs.
Bake cookies for 11-14 minutes. Once the cookies are out of the oven, use a round metal cookie cutter larger than the cookie to shape them. Sprinkle with flakey salt.