Bløtkake is a celebratory Norwegian layer cake that's decorated with whipped cream and fresh berries. I first had it at a Syttende Mai (Norwegian Constitution Day) party and have also had it at my husband's family's Christmas parties. This recipe is based on his family's recipe and was transcribed from a scribbley old notecard.
Ensuring all wet ingredients, especially eggs, are at room temperature will help achieve maximum volume when beating them with sugar, yielding a light, airy sponge. When incorporating dry ingredients, fold gently with a rubber spatula to avoid overmixing, which can develop gluten and result in a tough cake. It's crucial for the cake to be completely cooled before slicing and assembling; warm cake will cause the whipped cream to melt. For the most stable whipped cream, use very cold heavy cream and a chilled mixing bowl.