Combine evaporated milk, brown sugar, butter, egg yolks, and vanilla in a saucepan over medium heat. Cook, stirring constantly, at a low boil until mixture turns a light caramel color and thickens, about 10 minutes.
Remove from heat.
Mix the heavy whipping cream, add it to all mixing, and stir in coconut and pecans.
Let cool to room temperature before spreading on cake.