Espresso Cotton Cake 特濃咖啡棉花蛋糕

This is the coffee version of my Tang Mian Sponge Cake (or Cotton Cake). This time I lined my cake pan with cardboard before inserting my parchment paper. This step is not a must, but it could further reduce the rate of the heat conduction so the cake would be less likely to crack on top.
這是咖啡口味的燙麵法海綿蛋糕(或稱棉花蛋糕)。這次EC先在模具內側放入厚紙皮才鋪上牛油紙。這不是必須的步驟，可是加了紙皮之後有助減慢傳熱速度，蛋糕表面會比較不容易破裂。

For other cotton cake flavors, please visit my blog posts, Semi-Naked Drip Cake with Fresh Fruits and Whipped Cream and Tang Mian Chocolate Sponge Cake. Also visit my blog post, Pandan Cotton Cake
for similar cake that is made with oil.
其他棉花蛋糕口味可參考鮮果忌廉半裸淋面蛋糕和燙麵法朱古力海綿蛋糕。以液體油製作的古早味蛋糕配方則可參考古早味班蘭蛋糕。

Espresso Cotton Cake
特濃咖啡棉花蛋糕

For 8”x3” square cake pan
8”x3″四方模份量

Ingredients

90 g cake and pastry flour
2 Tbsp instant espresso powder
A pinch of salt
70 g unsalted butter
75 g milk
6 large egg yolks
6 large egg whites
1/2 tsp white vinegar or lemon juice (I use Korean apple vinegar)
75 g granulated sugar (I use organic cane sugar)

Note: the eggs I use are about 50-55 g each without shells

材料

低筋麵粉 90克
即溶特濃咖啡粉 2湯匙
鹽少許
無鹽牛油 70克
牛奶 75克
大蛋蛋黃 6隻
大蛋蛋白 6隻
白醋或檸檬汁(EC用韓國蘋果醋) 1/2茶匙
細砂糖(EC用有機蔗糖) 75克

註：EC用的大蛋每隻淨重約50-55克

Directions 做法

In a large bowl, mix together the flour, espresso powder and salt. Set aside. Line cake pan with parchment paper. Preheat oven to 325ºF/160ºC.
*For espresso powder that is not finely ground, dissolve it into warm milk first instead of mixing it into the dry ingredients.
*I trimmed cardboard pieces according to the inner dimensions of the cake pan then wrapped each with aluminum foil. I inserted these before lining the pan with parchment paper in order to further reduce the rate of heat conduction so the cake won’t crack easily.
大碗內混合麵粉，咖啡粉和鹽備用，模具內墊牛油紙，焗爐預熱至325ºF/160ºC。
*若咖啡粉並非呈幼細粉末狀可改與暖牛奶混合而不是與乾粉混合
*為了進一步減慢導熱速度防止蛋糕爆面，EC用紙箱的厚紙皮剪裁成模具內則的尺寸，包上錫紙放在模具的四周才墊牛油紙

Heat butter in a saucepan over low heat until it starts to bubble around the edges (best temperature is between 65 and 68ºC). Add flour mixture and whisk to form a smooth paste (i.e. the tang mian or cooked dough). Stir in warm milk in three batches until it becomes soft dough like. Whisk in egg yolks in two batches, stirring well after each addition. Batter will be glossy, smooth and runny.
*It is important to keep the temperature of the butter within range. If temperature is too high then the scalded dough will be lumpy.
牛油放小鍋小火加熱至邊緣冒泡(最佳溫度為65至68℃)，倒入乾粉攪拌成順滑燙麵糊，分三次拌入暖牛奶攪拌成軟麵糰，分兩次拌進蛋黃(每次要待蛋液完全被吸收才加另一次)，蛋黃糊應光滑無顆粒並呈流質。
* 請盡量控制牛油溫度，牛油太熱會令燙麵糰過硬不易攪拌

In an impeccably clean mixing bowl, beat egg whites and vinegar with the stand mixer fitted with the whisk attachment or an electric mixer until very foamy. Add sugar in batches and continue beating until firm peak forms. When you lift up the whisk, the meringue will stand up with a large curvy tip. Add one third of the meringue to the yolk batter and fold to lighten. Add remaining meringue in two batches. Fold gently and thoroughly with a spatula until homogeneous. Pour batter into pan and smooth top with a spatula. Tap pan against the table top several times to get rid of any large air bubbles.
把蛋白和醋放在無油無水的乾淨鋼盆中，使用廚師機或電動打蛋器打至泡泡變細密，分次加糖打至企身，拉起打蛋器時蛋白霜呈大彎勾狀，將三分一蛋白霜混入蛋黃糊中充份拌勻，餘下的蛋白霜分兩次加入用膠刮輕手以切拌方法混合至顔色均一，將麵糊倒入模中，抹平表面後將模具往桌上輕敲幾下敲出大氣泡。

Place cake pan into another bigger tray or roasting pan and fill the outer pan with warm water. Bake at 325℉/160℃ for 15 to 20 minutes. Drop to 300ºF/150ºC and bake for 60 to 70 minutes, filling the tray with more water if needed.
把一個大烤盆放在焗爐中，放進模具後將暖水注在烤盆內，以325ºF/160ºC焗15至20分鐘，然後降溫到300ºF/150ºC多焗60至70分鐘(自行注意烤盆水量)。

Switch off the oven while leaving the door ajar. Let the cake cool in the oven for 5 minutes. Remove cake from the pan and release the parchment paper from the sides. Let cool on a cooling rack and trim off the edges for a neater presentation. Serve immediately or chill and serve the next day.
關掉焗爐並微微打開焗爐門讓蛋糕慢慢降溫，5分鐘後取出蛋糕轉移到鋼架並拉下四邊牛油紙放涼，完全放涼後以長刀切掉四邊保持外觀漂亮，現做現吃或冷藏隔天進食皆可。