Heat the oven to 350°F (175°C), with a rack in the middle. Grease a 9-by-13-inch metal baking pan at least 2 inches deep. Distribute coconut across the bottom, then scatter pecans evenly over it.

Beat the softened cream cheese and butter until smooth. Add the powdered sugar gradually at low speed, then beat just until creamy. Set aside.

In a separate bowl, mix the specified cake mix with water, oil and eggs at medium speed for 2 minutes, following the current package. Pour the batter over the coconut and nuts without stirring the base.

Drop tablespoon-size spoonfuls of filling across the batter. Pass a butter knife through the top a few times, keeping distinct pale patches and leaving the bottom layer undisturbed.

Bake for about 50–60 minutes, starting checks at 45 minutes. The edges should be set, and the chocolate areas should spring back lightly. A tester in chocolate cake should show moist crumbs, not liquid batter; filling pockets can leave creamy streaks. If the top darkens early, tent loosely with foil and continue until the cake is baked through.

Rest the pan on a rack for 30 minutes. Cut into 15 squares and serve, or move portions to shallow containers and refrigerate promptly. Refrigerate within 2 hours of baking, or 1 hour above 90°F (32°C). Keep covered at 40°F (4°C) or below for 3–4 days.