Combine egg yolks, evaporated milk, and brown sugar in a saucepan. Add butter, and cook over medium heat, stirring constantly, until thick, about 10 minutes. Pour through a fine sieve into a bowl.
Stir in vanilla, salt, coconut, and pecans. Let cool completely. Frosting can be refrigerated in an airtight container for up to 1 day; bring to room temperature before using.