Preheat oven to 350ºF. Line two large cookie sheets with parchment paper.
In a medium bowl, whisk together flour, cornstarch, baking powder, and salt.
In a large bowl, cream butter, sugar and oil until light and fluffy.
Beat egg whites into butter mixture in two addition, until well combined.
Beat in extracts until well combined.
Add gel food color, a little at a time with a toothpick, until desired shade of pink is reached. (Adding remaining ingredients will lighten the color slightly.) Beat until evenly distributed.
Add flour mixture to batter and beat just until combined. Mix in white chocolate chips if using.
Roll dough into balls, about 2 tablespoons each. I used a #30 portion scoop.*** Roll dough very generously in powdered sugar. Place two inches apart onto prepared cookie sheets.
Bake until cookies are puffed and tops are set, about 11-13 minutes. Transfer cookies to a cooling rack.