Set your oven to 350°F (180°C) and line an 8×8-inch baking pan with parchment paper or aluminum foil, leaving a bit of extra hanging over the edges. This makes it easy to lift the brownies out once they’re done baking.

In a large heat-safe bowl, mix together the butter, sugar, cocoa powder, and salt. Melt the mixture in the microwave in 30-second intervals, stirring between each, until the butter is fully melted (alternatively, use a small saucepan over medium-low heat). It’s fine if the texture looks a bit gritty. If the mixture feels hot, let it cool for a few minutes until it’s just warm.

With a whisk or rubber spatula, stir in the vanilla extract. Add the eggs one at a time, stirring after each addition, until the batter becomes thick and glossy. Mix in the flour until well combined and the batter is shiny and dense. Spread the batter evenly in the prepared pan, smoothing the top.

Bake for 20-25 minutes, until a toothpick inserted in the center comes out with a few moist crumbs. Once baked, remove the pan from the oven to add the pecan layer on top.

As the brownies bake, prepare the pecan layer: In a saucepan, melt the butter with the sugar and corn syrup or maple syrup, stirring continuously until the sugar fully dissolves.

Allow the mixture to cool a bit, then whisk in the remaining ingredients, folding in the chopped pecans at the end. Stir until well combined.

Carefully pour the pecan mixture over the baked brownies, using a spoon or small offset spatula to gently spread it to the edges. Bake until the pecan layer is golden and set, about 20 to 25 minutes.

Cool completely on a wire rack, and for best results, let it chill in the fridge for a few hours before cutting into squares.