Combine the flour, cornstarch, baking powder, and salt in a bowl. Set aside.
Using a mixer, mix the sugar and butter until smooth. Add the eggs and orange extract, beating at medium-low speed until combined.
Gently add in half of the flour mixture, then beat until combined. Add the remaining flour and combine.
Stir in chocolate chips and mix. Then cover and refrigerate for 30 minutes to 2 hours.
Preheat the oven to 350°F. Line a baking sheet with parchment paper. Place the dough on parchment paper using a small ice cream scoop, leaving enough space for some spreading. Sprinkle each cookie with fleur de sel or sea salt. Bake for 22-15 minutes or until lightly brown on the edges.