In Spain it is called sobao pasiego. A Cantabrian butter sponge cake baked in a paper mold. I first tasted it one Summer when our tour bus on our way to San Sebastian stopped by a small town to sample the pastry. It reminded me of the madeleine but it was sweeter and heavier with butter or lard. I liked it a lot but thought of making it with less sugar and butter. I had to learn how to make the paper mold for the authentic look. I use parchment paper for this. I sometimes make them at home a little lighter for breakfast or for snack. For every cup of flour I put 1/2 cup of sugar, 1/2 cup of melted butter, 2 large eggs separated, 1/2 tsp of baking powder, some lemon rind, a tsp of rum or anisette and a pinch of salt. I add a little oil if the batter is too thick. I start off by beating together the butter, salt, lemon rind, rum and the sugar until light and creamy, gradually adding the yolks. I beat the egg whites until stiff then mix half of it carefully to the butter mixture and fold in the sifted flour with the baking powder and then the remaining egg white. I fill the mold 3/4 full and bake in a 350F oven for 15 minutes or until golden.
The distinctive flavor of this treat is the lemon rind and rum or anisette but you can also add a drop of vanilla extract if you wish.
I love to eat them with a glass of cold milk.