Preheat your oven to 350°F (175°C). Line an 8-inch square baking pan with aluminum foil and lightly coat it with cooking spray.

In a mixing bowl, combine unsalted butter, all-purpose flour, confectioners’ sugar, cornstarch, vanilla extract, and salt. Beat until it forms a soft dough, about 2-3 minutes.

Press the dough into the bottom of the prepared pan, smooth the surface, and pierce with a fork. Bake for 12-13 minutes until just set.

While the crust is baking, whisk together corn syrup, water, and vanilla extract. In another bowl, beat softened butter, granulated sugar, and salt until creamy. Incorporate eggs and flour mixture, then fold in chocolate chips.

Pour the filling over the crust, spread evenly, and bake for 23-25 minutes until the edges are set.

Let cool in the pan for at least 2 hours before slicing into squares.