In a medium pot, whisk the evaporated milk, butter, sugar, brown sugar, and egg yolks to combine. Cook over medium-low heat, whisking constantly, until the mixture begins to simmer. Continue to cook, stirring frequently to prevent sticking and/or clumps forming, until the mixture is thick like pudding, 13 to 15 minutes.
Stir in the pecans, coconut, and vanilla and cool for 20 to 30 minutes.
Transfer the cooled chocolate cake doughnuts to a parchment-lined baking sheet.
Spread the cooled frosting on top of each doughnut in an even layer. Serve immediately!
I always carry three kinds of hot sauce in my purse. I have a soft spot for making people their favorite dessert, especially if it's pie. My first cookbook, The Fearless Baker, is out on October 24, 2017.