Cake:3/4 cup of brown sugar3/4 cup of 35% whipping cream1/2 cup of softened butter1 and 1/4 cup of flour1 teaspoon of baking powder2 egg yolks3 egg whitesA pinch of salt1 teaspoon of vanilla extract1/4 teaspoon of ground cardamomIcing:1/2 cup of brown sugar1 cup of 35% whipping cream1 teaspoon of butter1 pinch of saltWalnuts (to taste)