Coffee cake base
45g cake flour
35g granulated sugar
25g vegetable oil
35g hot water
6g coffee powder/instant coffee
3g lemon juice
3g vanilla extract
Notes: By cake flour, I mean low protein flour, which normally contains 7-9% protein (Mine is around 8%). Not self-rising flour.
Coffee Cake Base
- In a clean bowl, separate the eggs. Keep the egg white bowl cool in the fridge.
- In a cup, mix well coffee powder and hot water until powder dissolve. In a clean bowl, mix well coffee liquid and vegetable oil, sift in cake flour and mix well. Add in 3 egg yolks, mix until well combined. Set aside.
- Preheat the oven to 320℉(160℃) . Take the egg white bowl out of the fridge, add in sugar, lemon juice, and vanilla extract, and use a hand mixer to beat until it forms soft peaks.
- Take a scoop of whipped egg white and gently fold into the batter until just combined. Pour the batter into rest of the whipped egg white and gently fold the whipped egg white into the batter until just combined.
- Line the baking pan (28*28*2.6 cm) with baking mat or parchment paper. Pour all the batter into the baking pan, gently smooth its surface, give the pan a tap or two, and send into the oven to bake for 28 minutes or until its surface turns golden brown.
- Take the cake out of the oven right away and let it cool down on the cooling rack. Wait until its surface is cool to touch, release the sides with an icing spatula, and quickly turn the cake upside down on parchment paper and remove the pan. Peel off the baking mat or parchment paper.