Preheat the oven to 350 degrees, and generously grease a 9x13 inch pan, and set the pan aside. In a large bowl, whisk together the melted butter, brown sugar, and regular sugar until smooth. Whisk in the eggs, milk, and vanilla extract until the mixture is smooth.

Add the flour and salt to the mixture, and stir until combined. Gently stir in the chopped chocolate and chopped pecans, working quickly because the batter will be starting to thicken as the butter comes back to room temperature.

Spread evenly in your prepared pan, and press some extra chocolate and pecans into the top. Optionally, sprinkle some flakey salt on top as well. Bake for 28-30 minutes, or until a toothpick inserting about 2 inches from the edge of the pan comes out clean. Cool completely, slice, and serve!