• Cook milk, 1st measure of sugar, vanilla, and salt in medium saucepan until simmers.
• Whisk together yolks, cornstarch, and 2nd measure of sugar.
• Pour hot milk mixture one cup at a time into yolk mixture.
• Pour mix back into saucepan; cook on medium high, whisking constantly until thick (about 2 minutes).
• Transfer to a mixing bowl with paddle.
• Add butter to hot mixture.
• Mix until cool (about 5 minutes).

Assembly

• Slice cake into 3 equal layers (set aside top 2 layers).
• Spread pastry cream onto cake layer, and top with cake layer (alternate until there are two layers of pastry cream and three layers of cake, ending with cake at top).
• Ice cake with favorite fudge icing, chill until ready to serve.