Preheat the oven to 350 degrees F. Grease a 9- by 13-inch square metal baking dish and line with parchment paper, allowing several inches to hang over on at least two sides of the pan. Lightly grease the parchment paper.

Combine the flour, powdered sugar, cubed butter, cocoa powder, and salt in a mixing bowl and, using your fingers or a pastry blender, cut in the flower until the mixture resembles damp sand. It should hold together when squeezed between your fingers. Press the mixture onto the bottom and slightly up the sides of the prepared pan. Bake until the crust is fragrant and lightly toasted, about 15 minutes. Remove from the oven and transfer to a wire rack. Sprinkle the chocolate chips over the crust and let cool completely.

In a medium bowl, whisk together the brown sugar, corn syrup, evaporated milk, melted butter, eggs, and vanilla. Stir in the coconut and pecans, then pour the pecan mixture over the cooled crust. Bake until golden brown and set, 28 to 32 minutes. Transfer to a wire rack to cool completely, then refrigerate until firm, at least 1 hour, before removing from the pan.

When ready to remove, simply lift up on the parchment “handles” and transfer to a cutting board. Cut into bars about a scant 2-inches square.

Serve at room temperature.