2 cups (500 ml / 1 pint)milk(lukewarm) (full fat or low fat but not zero fat)
To Serve (optional)
Icing sugar(powdered sugar), for dusting
Preheat oven to 325F/160C (standard oven / fan forced or convection)
Butter a 8" x 8" / 20cm x 20cm square cake tin (Note 4).
Beat egg whites with a mixer until stiff peaks form. Set aside.
Place the egg yolks and sugar in a bowl and beat until it turns pale yellow - about 1 minute.
Add the vanilla extract and butter and beat until well incorporated - about 30 seconds to 1 minute.
Add the flour and beat until just combined.
Pour the milk in slowly while beating, and beat until well combined (or if using a hand held mixer, add 1/4 milk at a time, beating in between).
Use a spatula to fold in the egg whites in the batter, one third at a time, until just incorporated. You don't want to knock the air out of the egg whites. Don't worry if there are a few egg white lumps in the batter. The batter should be very thin, almost like a thick pouring cream.
Pour the batter into the prepared cake tin.
Bake until the top is golden brown and the cake does not "jiggle" when you gently shake the tin - around 40 to 50 minutes. Check the cake at 30 minutes - if the top is already golden brown but the cake is not yet set (i.e. it jiggles), cover loosely with foil and return to the oven, 10 minutes at a time, until set.
Allow to cool in the tin for 10 minutes, then turn out onto a cooling rack.(Note 3) Cool completely before serving.
Cut into squares - I cut it into 12 in the photo, but 9 is more realistic serving size portions.
Dust with icing sugar just before serving.
Serve with a side of whipped cream and strawberries, if using.
1. Australia vs US vs UK measurements - I made this recipe 5 times. 3 of the 5 times, I weighed the ingredients, once I used Australian cups and once I used US cups. I couldn't tell the difference in the end result.2. The baking time for this cake will differ depending on the oven. Of the 5 times I made this cake, the bake time differed by 15 minutes. Once it was 40 minutes, 3 times it was 50 minutes and once it was 55 minutes. It takes Jo from Jo Cooks (recipe source) 70 minutes, but she says her oven is weak.The safest way to get the baking time right is to follow these directions: a) The cake is ready when the top is golden brown and the cake doesn't "jiggle" when you gently shake the pan. If it jiggles, there is still raw batter inside. b) I found that 4 of the 5 times I made it, the top became golden brown before the cake was set. c) So to get the bake time right, check it first at 30 minutes. If the top is golden brown, cover loosely with foil and return to the oven until the cake is set. Check every 10 minutes - any longer, and you'll risk the cake overcooking.3. Tor get the cake out of the tin, just turn it out like a normal cake. The custard is set, it is not like super soft jelly. What I do is place a cutting board on top of the tin, flip it upside down (it slips right out) then place a cooling rack on top then flip it again (so you end up with the right side up on the cooling rack).4. I myself have not tried this in a glass pan but readers have - if you scroll through the comments, you will find feedback from a reader on 3 February 2017 confirming this!5. Nutrition assuming 1 cake is cut into 9 pieces. Note that I cut the cake into 16 pieces for the photo but that is far too small!SaveSave