Preheat your oven to 350°F (175°C). Grease and line a 9x13 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal later.
In a large bowl, mix together the flour, cocoa powder, sugar, baking powder, and salt. Pour in the melted butter, 1 large egg, and 1 teaspoon vanilla extract. Stir until a dough forms.
Spread the dough evenly in the bottom of the prepared baking pan, pressing it down to form an even layer. Bake in the preheated oven for 15 minutes, then remove and let cool slightly.
In another bowl, whisk together the corn syrup, 2 large eggs, 1 teaspoon vanilla extract, and sea salt until well combined. Fold in the chopped pecans and chocolate chips until evenly distributed.
Pour the filling mixture over the cooled crust, spreading it out evenly to cover the base.
Return the pan to the oven and bake for an additional 30–35 minutes, or until the filling is set and edges are slightly puffed.
Once done, remove the pan from the oven and let it cool completely in the pan on a wire rack. Once cooled, lift the bars out using the parchment overhang and cut into squares or rectangles.
Notes
Serve the bars on a beautiful platter, and dust with powdered sugar for a touch of elegance. Pair with a scoop of vanilla ice cream or whipped cream for an extra indulgent treat.