In a medium saucepan, whisk together sugar, evaporated milk, egg yolks, and salt until smooth. Add butter, and cook over medium heat, whisking frequently, until butter is melted. Cook, whisking constantly, until thickened and coats the back of a spoon and an instant-read thermometer registers 200°F (93°C), about 5 minutes.

Remove from heat, and stir in coconut, pecans, and vanilla. Pour into a heatproof bowl, and cover with plastic wrap, pressing wrap directly onto surface of filling to prevent a skin from forming. Refrigerate for at least 2 hours or up to 3 days.