Preheat the oven: Set the oven to 350°F (175°C).
Prep the pan: Line an 8 x 8 inch square baking pan with parchment on the bottom and all four sides, then lightly grease the parchment and set aside.
Melt butter and chocolate: Add the butter and chopped chocolate to a large heatproof bowl and microwave in 15 to 30 second intervals, stirring between each, until smooth. Valrhona Hukambi chocolate is what I used, but pick any good chocolate that suits your taste.
¾ cup unsalted butter, 1 cup Valrhona Hukambi chocolate
Add sugar: Whisk in the granulated sugar until fully combined. Feel free to use standard granulated white beet sugar. I chose raw cane sugar for the warm flavor notes of caramel, maple, toffee, and a touch of earthiness.
1½ cups raw cane sugar
Add eggs one at a time: Whisk in the eggs one at a time until each is fully incorporated before adding the next. Use a metal whisk, or a handheld Mixer on low.
3 large eggs
Add vanilla: Add the vanilla with the final egg and whisk again until smooth.
1 teaspoon vanilla extract
Add dry ingredients: Sift the flour, cocoa powder, and salt together, then add to the bowl and fold until just combined.
¾ cup all-purpose flour, ½ cup unsweetened 16% cocoa powder, ½ teaspoon salt
Add mix-ins: Fold in the chopped pecans and chocolate chips or chopped chocolate until evenly distributed.
½ cup pecans, ½ cup chocolate chips
Pour and level: Transfer the brownie batter into the prepared pan and smooth the top.
First bake: Bake for 40 to 45 minutes until the edges and top look set but the center is not fully baked. If your oven runs hot or is convection, start checking around 35 minutes.
Prepare Pecan Caramel Topping: Make the pecan caramel topping during this first bake to keep the timing seamless. Combine ingredients in a medium saucepan, add the chopped pecans, butter, maple syrup, brown sugar, corn syrup, and salt, then stir to combine.
Boil and finish: Bring to a boil over medium heat and let it simmer for 3 minutes, then remove from heat and stir in the vanilla.
Add topping to brownies: Remove the brownies from the oven once set around the edges and pour the hot pecan caramel topping evenly over the surface, spreading gently with an offset spatula.
Second bake: Return the pan to the oven and bake for another 15 minutes.
Cool and serve: Remove from the oven and allow the brownies to cool completely before slicing.