Preheat the oven to 350 F and line two baking sheets with parchment paper.
Rub the granulated sugar and orange zest together until fragrant. Beat this orange sugar with the butter until light and creamy.
Mix the egg, vanilla, and orange extract into the butter mixture. Add the flour, cornstarch, baking powder, and salt, then mix just until a soft dough forms.
Fold the white chocolate chips into the dough. Divide the dough into 12 portions and arrange them at least 2 inches apart on the prepared baking sheets.
Bake for 10 to 12 minutes, until the edges are set and the centers still look soft. Cool the cookies completely on a cooling rack.
Whisk the powdered sugar, orange juice, heavy cream, and orange zest until smooth. Drizzle the glaze over the cooled cookies and let it set for 20 minutes.