Melt the butter in a large saucepan over medium heat. Whisk in the evaporated milk, brown sugar, and egg yolks and bring to a simmer over medium heat. Simmer, stirring constantly with a wooden spoon, for about 15 minutes, until slightly thickened. If the mixture looks a bit curdled, beat it vigorously with a whisk. Off the heat, stir in the vanilla extract, almond extract, coconut, almonds, pecans, and salt. Allow to cool for about an hour. Frost the cupcakes with a knife or small metal spatula.