Preheat oven to 350° and grease a bundt cake pan (I don't flour it).
Follow directions on the Duncan Hines box for both the cake and the chocolate filling. They will be mixed in two separate bowls.
Coconut Pecan Frosting
Put the butter, toasted coconut, toasted pecans, and salt in a medium bowl and set aside.
In a small saucepan, heat the evaporated milk, both sugars, and egg yolks over medium heat. Stir the mixture constantly, until thickened. If using a candy thermometer, bring heat to 195°. Pour the mixture over the coconut pecan mix (from step 1) and stir until the butter melts.
Put frosting in the refrigerator to cool completely, about 15-20 minutes. You want it to still be pliable, not solid.
Frost the top of the bundt cake to look like a cake donut, as pictured above.