Preheat the oven to 350F then line an 8x8 pan with parchment paper and set aside.
In a large bowl, add in the flour, salt, and cornstarch and mix. Add in the melted butter, sugar, and vanilla, and mix until cookie dough forms. Press onto the prepared baking pan and bake in the preheated oven for 15 minutes. Once it's done, remove the crust and reduce the oven temperature to 325F.
6 tbsp butter, 1/3 cup granulated sugar, 1 tsp vanilla extract, 1 cup all-purpose flour, 3 tbsp cornstarch
Filling
In a separate large bowl mix the egg, brown sugar, light corn syrup, heavy cream, salt, vanilla extract, and cornstarch until combined. Stir in the pecan pieces and the chocolate chips.
1/4 Tsp salt, 1 tsp vanilla extract, 1/3 cup heavy cream, 1 egg, 3/4 cup brown sugar, 1/3 cup light corn syrup, 1 tsp vanilla extract, 1/2 tsp salt, 1 tsp cornstarch, 1 & 1/2 cup pecans, 3/4 cup chocolate chips
Pour the pecan pie filling on top of the crust and bake for 25 minutes. The edges will brown a little and the center will be barely jiggly.
Remove from the oven and let cool completely before transferring to chill in the fridge for at least an hour. Slice the bars and serve.