Why do we have to cream butter and sugar for cakes?

Let it be light: Creaming butter and sugar gives a spongier result.
Let it be light: Creaming butter and sugar gives a spongier result. Photo: William Meppem

Why do cake recipes always call for butter and sugar to be creamed? Why not just add melted butter to the sugar? M. Redwin

We get this query coming in frequently so it is obviously vexing a quite a few people. Butter is an emulsion of water in fat – about 15 per cent water, the rest mostly butterfat. When you cream (beat) sugar with butter, the water in the butter starts to dissolve the sugar while air is trapped as tiny bubbles in the fat. When flour is added to the creamed butter and sugar to make the batter, then subsequently baked, the air expands but is trapped by the elastic protein in the flour. Sometimes, however, you don't want that spongy, springy dough. You want a chewier texture such as in a muesli slice, where adding sugar to melted butter is more applicable.

To avoid filling the house with the smell of fish I cook salmon fillets slowly, either sous vide or in the oven. When I do a white substance covers the fillets, making them unattractive. When I cook them in a frypan with a higher heat this doesn't happen. Why? J.Griffin.

Ingredients such as green tea, cinnamon, ginger, clove, bay and sage contain compounds that help reduce odour by stopping fatty acid oxidation and neutralising the compound TMAO (trimethylamine N-oxide) that creates the fishy odour. The white material is solidified protein from cell fluid that starts to escape from the flesh at around 20C. When you pan-fry the fish exactly the same thing happens except that at the higher temperature the Maillard reaction occurs, giving this leached protein a golden crust and creating those delicious dark flavours. Solution? Scrape the cooked protein off your sous vide salmon before serving. Alternatively, cover the fish with a sauce. Consider a salsa with lots of chopped tomato, onion, fresh coriander and lime. Another way of serving the salmon would be to break it apart with your hands and fold through a salad of small greens then dress with a vinaigrette.

Whatever happened to spaghetti squash? A. Hayden

This was the Iron Chef Australia of the vegetable world. It was launched with much fanfare and then, to use a TV industry term, died in the arse. It's a large squash, like a Lebanese zucchini that has been gorging on steroids, that has a fibrous interior that can be forked out like stringy but less sweet pumpkin. After its Australian debut in the late 1980s and subsequent demise, it seems to be making a comeback, with some supermarket distribution of spaghetti squash under the Hatters brand. To cook, slice in half lengthways, spoon out the seeds, place face down on a baking tray and cook in an oven preheated to 190C for 30-40 minutes or until soft. Fork out the interior. I have tried to serve it to the kids with bolognese sauce but have had more success serving it as a warm salad dressed with walnuts, parsley, chopped anchovies, lemon juice and extra virgin olive oil.

Slicing boiled eggs – the sequel

In regards to slicing a hard boiled egg, several readers, including chef Victor Liong of Melbourne's Lee Ho Fook, suggested tying a piece of cotton, dental floss or fine fishing line to an immovable object, making the line taut, then pulling this down through the boiled egg to slice it.

Letters

This week's digital mailbag at the Brain Food Institute is virtually bursting at the seams. Thanks to I. MacKenzie, whose Gaelic-speaking parents schooled him in the joys of porridge. "I was taught … the correct way (to eat porridge) is to have a separate cup of milk on the side and dip your spoon of porridge into that before putting it into your mouth.  By eating in this way the porridge will hold its heat in the bowl but still be cool enough to be able to swallow."

If you have a vexing query email brainfood@richardcornish.com.au

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