Chef John's Pecan Pie Brownies

Preparation - Preheat the oven to 325 degrees F (165 degrees C). Line an 8x8-inch baking pan with enough parchment to overhang on all sides, and oil the parchment.

Brownie Base - To make brownie batter, combine white sugar, cocoa powder, kosher salt, and 10 tablespoons melted butter in a mixing bowl. Mix with an electric hand mixer or whisk until combined. The mixture will look grainy, but that's okay.

Brownie Base - Add 1 teaspoon vanilla and 1 egg, and mix with a whisk or electric hand mixer until combined. Again, the mixture will look grainy. Add the second egg, and continue mixing on high speed until a smooth, thick, glossy batter is formed.

Brownie Base - Add flour and mix on low speed until flour just disappears. Use a spatula to mix in any flour from the side of the bowl; spread batter evenly into the prepared pan. Tap pan gently on the counter to level the brownie base.

Brownie Base - Bake brownie base for 20 minutes. Remove to cool on a wire rack while making pecan pie filling.

Oven Adjustment - Increase oven temperature to 350 degrees F (180 degrees C).

Pecan Pie Filling - For pecan pie filling, combine brown sugar, salt, 1 teaspoon vanilla, corn syrup, 2 eggs, and melted salted butter in a bowl; whisk until smooth. Stir in pecans; pour filling over brownie base and spread evenly; tap pan gently on counter to level the filling.

Baking - Bake in the preheated oven until pecan pie filling is almost fully set, about 1 hour. If dish is shaken gently from side to side, there will be a very slight jiggle in the center.

Cooling and Serving - Let cool completely, about 30 minutes. For best results, cover and chill before cutting. Lift brownies from the dish using parchment overhang. Cut into 16 2x2-inch squares.