Quatre-quart mysterieux

I had an absurd desire to bake something this weekend. I also had a couple overripe bananas. I thought about a basic banana bread but then I remembered the somewhat vague quatre-quart recipe from the Observer Food Monthly I linked the other day and decided to try that instead.

To be fair, all quatre-quart recipes are somewhat vague. That's really part of their beauty -- they're very flexible. The guiding factor is, 'how much of X do I have?' where X = one of the essential four ingredients. Usually that's eggs.

So, I weighed 3 eggs. 200g. Fine. I bunged 200 g each butter and sugar into the bowl of my mixer, and creamed them. Then I beat in the eggs, and 200g flour, plus a spoonful of baking powder (sifted in with the flour), and a spoonful of vanilla extract.

Carmelising overripe bananas leaves you with an excellent mush. I decided to fold my banana mush into the batter, and added some chopped semi-sweet chocolate while I was at it (about 1 oz.) since I didn't have any Twix bars (as suggested in the Observer).

I scraped all that into a loaf pan and tossed it into a 350 F oven. This is where things got weird.

The sides of the cake rose faster than the centre and flopped over onto it.



Later the centre rose too, and in the end it was all fine. Nice fluffy crumb, banana and chocolatey bits marbled through as desired, and a' that.



I'm just baffled by the way it rose, though. Never had a cake do that before. Thinking about it, I don't think there's any salt in this (I didn't add any and the butter was unsalted). Did that maybe have something to do with it?