01 -
Heat the oven to 350°F (175°C). Grease a 9x13-inch baking pan well, including the corners.
02 -
In a large bowl, combine the cake mix, water, oil, and eggs. Beat for about 2 minutes, scraping the bowl once, until the batter is smooth.
03 -
Pour the batter into the prepared pan and smooth the top. Bake for 30-35 minutes, until the center springs back and a toothpick comes out with a few moist crumbs.
04 -
Let the cake cool for 5 minutes. Use the handle of a wooden spoon to poke holes across the cake, spacing them about 1 inch apart and going nearly to the bottom.
05 -
Whisk the sweetened condensed milk with 1/2 cup caramel sauce. Pour slowly over the warm cake, guiding the mixture into the holes with a spatula.
06 -
Beat the softened butter until creamy. Add powdered sugar, 3 tablespoons milk, vanilla, salt, and the remaining 1/2 cup caramel sauce. Beat until smooth, adding 1 more tablespoon milk only if needed.
07 -
Stir the toasted pecans and shredded coconut into the frosting by hand until evenly distributed.
08 -
Spread the frosting over the cake. Cover and refrigerate for at least 1 hour before slicing, or overnight for the cleanest texture.