In a medium saucepan, combine evaporated milk, egg yolks, brown sugar, and butter. Cook mixture over medium heat, stirring constantly - until thickened (approx. 10-15 minutes). Once it comes to a light boil, and is thickened, remove from heat and strain through a mesh strainer into a mixing bowl. Stir in vanilla then mix in shredded coconut and chopped pecans. Allow to cool at room temperature before frosting.