Surabaya Cake (Indonesia Egg Yolk Sponge Cake) 全蛋黄海绵蛋糕

准备Lucius的第二个生日蛋糕时一不小心打翻了整碗蛋白，就这样多出了7颗蛋黄。蛋黄的保鲜时间比蛋白短，我马上想到了Surabaya Layer Cake (Lapis Surabaya)。

Lapis Surabaya是印尼著名的蛋糕，口感类似千层糕（Kek Lapis）但是只有三层，两层原味（黄色）夹着一层巧克力味，传统的夹层为草莓酱。我因为不想再敲鸡蛋，所以只做了一片原味蛋糕（加了香草精），一分为二叠起来变成两层。少了巧克力蛋糕，夹层就用巧克力酱来代替。

蛋糕的组织和我吃过外面卖的有点不同，有点松散（是因为用自发粉吗？原食谱还另外加发粉但我都省略了），不如外面卖的密实和湿软，但是蛋糕非常的柔软轻盈，有点入口即化的感觉（其实外面卖的我也只吃过一家，给我的感觉是蛋糕里肯定加入了不少乳化剂）。

把蛋糕包装了送人，自己只留下修饰后剩下的蛋糕。

This is my simplified version of the famous Indonesia Subaraya Cake.

Surabaya Cake (Indonesia Egg Yolk Sponge Cake)

Ingredients:
7 egg yolks
50g castor sugar
1 tsp vanilla extract
90g butter (melted)
¼ tsp salt
45g self-raising Flour (sifted)

Filling: chocolate ganache (or any fruit jam, kaya etc)

Method:
1) Whisk egg yolks together with sugar until thick and creamy. Add vanilla extract salt. Give it a gentle thorough stir. Gently fold in sifted flour, alternating with melted butter until there are no more lumps of flour.
2) Pour into a lined and greased 9" square baking pan and bake at 175°C for 20 minutes or turns golden. Cool on wire rack.
3) Cut the cake into half equally. Spread chocolate ganache (or your preferred fillings) on one piece of cake. Top with another piece of cake. Trim the sides if needed.

(Recipe adapted and modified from http://www.best-dessert-recipes.com/surabaya-layer-cake.html)