Preheat oven to 350°. Line two large baking sheets with parchment paper.
In a bowl of stand mixer or handheld mixer, cream together butter, granulated sugar and brown sugar until light and fluffy.
Add in egg and vanilla. Mix until well combined.
In another bowl whisk together flour, cornstarch, baking soda and salt. Add mixture to wet ingredients. Mix until smooth. Dough will be thick.
Using a small cookie scoop or ice cream scoop, scoop tablespoon balls of dough onto baking sheets. Press down lightly on each cookie to flatten slightly.
Bake for 9-10 minutes or until edges start to brown.
Remove from oven and let cool for a few minutes. Transfer to cooling rack and let cool completely.
In the meantime, mix together cream cheese, powdered sugar and vanilla to make the frosting.
Using a spoon or spatula, coat tops of each cookie with frosting.
Put 1/4 cup of granulated sugar in a bowl. dip each frosted cookie top into sugar.
Using a kitchen torch, carefully torch each sugar coated top until brown and caramelized.
Store in air tight container in fridge for up to 4 days.
Enjoy!