Preheat the oven to 350°F. Spray a 13 x 9-inch baking pan with cooking spray. Set aside.
Spread the pecans and 1/2 cup coconut on a sheet pan in a single layer. Toast the nuts for 6 minutes, then remove to cool. Toast the coconut for 6-8 minutes total stirring periodically for even browning, Set aside to cool.
Prepare the butter cake per the package directions. After preparing the batter mix 1 cup flaked coconut into the batter by hand.
Spread the cake batter evenly into the pan. Bounce the pan a few times on the counter to remove any trapped air bubbles..
Bake for 25 minutes or per the package instructions until golden and a tester inserted into the center comes back clean.
Remove from the oven and immediately poke the cake generously using a fork.
Pour 1 cup caramel over the hot cake. Spread evenly gently pressing into the holes. Cool completely.
After cooling, frost the top with whipped cream. Drizzle with the remaining caramel and sprinkle with kosher salt. Top with toasted coconut and pecans.
Store leftovers chilled.