Make the cookie dough: Place 1 cup cold cubed butter, 1 cup dark brown sugar and ½ cup sugar in a stand mixer. Use the paddle attachment and cream for 5 minutes on medium.
Prep the dry ingredients: While the sugars and butter are creaming, in a separate bowl mix together the 2 ¼ Cup flour, 2 tablespoons cinnamon, 1 tablespoon cornstarch, 1 teaspoon baking soda and 1 teaspoon salt. Don't add the flour mixture yet, just leave until needed.
Add the eggs and vanilla: Stop the mixer and scrape down the bowl and add one egg. Mix it in for about 30 seconds and then stop the mixer again and scrape down the sides. Add the second egg and vanilla. Mix until light and fluffy.
Now add the flour mixture: Stop the mixer and add in the flour mixture. Stir on slow just until the flour is blended in.
Add the fillings: Stop the mixer and scrape down the sides and add in the roasted2 cups of diced dried mango, 1 ½ cup crushed meringues and 12 oz white chocolate chips. Mix on low just until everything is coated.
Make Dough Balls. Line a baking sheet with plastic wrap. Use an ice cream scooper to scoop out all the dough into balls and place them on the lined baking sheet. You should have about 25-27 scoops of dough. Chill. Cover the top of the dough with plastic wrap and chill overnight.
Bake. The next day pre-heat the oven to 375F and take out the tray of cookie dough from the fridge. Line your baking sheets with baking parchment or silpats and place 6 cookies on the sheet at least 2 inches apart.Bake for 5 minutes and then rotate the tray 180 degrees and bake for a further 4 minutes. Cool the cookies: Take the Mango Float Cookies out of the oven and leave to cool for 5 minutes and then transfer the cookies to a wire rack to fully cool down. Repeat baking steps for the rest of the cookies. See notes on how to freeze.