Are you celebrating a birthday and want to make a really yummy festive cake? This vanilla custard layer cake with chocolate is my absolute favorite one and no birthday seems right without it. In Denmark birthdays and layer cake go hand in hand. For Danes a really good layer cake usually consists of mouse with thin layers of sponge cake and lots of whipped cream. The mouse may have added flavors or be plain vanilla. I normally don’t use a recipe when I make this type of cake for family and friends, but that is easy for me to say since I have made hundreds of these layer cakes over…