In a large, heavy saucepan, combine the milk with 3/4 cup of the sugar and bring to a boil. Whisk in the semolina and cook over low heat, whisking often, until thickened, about 2 minutes. Stir in half of the butter and the remaining 3/4 cup of sugar and transfer to a large bowl. Let the semolina cool completely, stirring occasionally. Stir in the remaining butter, then stir in the 3 whole eggs, 9 egg yolks and the vanilla.