Preheat the oven to 350°F. Line a 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal.

In a medium saucepan, melt the butter and chopped chocolate over low heat, stirring until smooth. Remove from heat and let cool slightly.

In a large mixing bowl, combine the granulated sugar, brown sugar, and eggs. Whisk until well blended. Stir in the melted chocolate mixture and vanilla extract.

Add the flour and salt to the chocolate mixture, stirring until just combined. Fold in the chopped pecans.

Pour half of the brownie batter into the prepared baking pan, spreading it evenly. Spoon the pecan pie filling over the brownie layer, then top with the remaining brownie batter, spreading it gently to cover the filling.

Bake for 30-35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Allow to cool in the pan for at least 15 minutes before lifting out using the parchment paper. Let cool completely on a wire rack before cutting into bite-sized squares.