This is another delicious cake from the Cake Mix Doctor's Chocolate book. Since it stays in the pan, it's easy to take to a potluck. Everyone will ask for the recipe. The frosting is divine; good enough to eat with a spoon.
Place a rack in the center of the oven and preheat the oven to 350 degrees.
Grease and flour a 9x13" cake pan.
In a large mixing bowl, place the cake mix, cream of coconut, sour cream, oil, and eggs. Mix with an electric mixer on low for 1 minute.
Stop the mixer and scrape down the sides of the bowl. Increasing the mixer speed to medium, mix for 2 more minutes, until the batter is well blended.
Pour the batter into the prepared pan, smoothing the top with a spatula.
Bake the cake for 40 minutes. It's done when it springs back when lightly pressed with your finger. It might need up to 5 more minutes, depending on your oven.
Remove the pan from the oven and cool, in the pan, on a wire rack.
Prepare the frosting:.
Place the chocolate in a small glass bowl in the microwave, and melt on high power for 90 seconds. Stir until all the chocolate has melted. Set aside.
Place the cream cheese in a large mixing bowl. Blend with an electric mixer on low for 30 seconds. Add the melted chocolate, and blend with the mixer on low for another 30 seconds or so, until the chocolate is incorporated.
Add the milk, vanilla, and 3 ½ cups of the powdered sugar. Blend on low speed for 30 seconds. Add up to ½ cup more sugar as needed to make the frosting a spreadable consistency. Mix on medium speed for 1 more minute, until the frosting is fluffy.