I have seen different variations online. Some are interesting, some aren't. This is one version I have kind of settled in after some tries and changes and mixings with other recipes. It still is evolving, but is a good start point, or of course end point.
(Yeah, microwave oven. It works. This is kind of a survival recipe; it won't be as good as with a normal oven, but is incredibly fast (15 mins from beginning to cake), and it is better than a lot of sponge cakes and muffins you see in supermarkets and even coffee shops. Yeah, it also works for muffins. And if you don't have a normal oven in your rented flat, it's actually more than good enough)
- 4 eggs
- 450 g flour (substitute about a third of it with Graham for more interesting texture; or change to 300 g flour+200 g cocoa for a chocolate sponge cake)
- 450 g sugar (no big difference with brown sugar)
- 1.5 glasses of milk (can be substituted with juices. Orange, lemon are good. Lime is interesting! Also add grated orange or lemon zest)
- baking powder (can be substituted with a heaped coffee spoon of sodium bicarbonate for this quantity of flour. Beware if using acid juices or yoghurt, might need more powder)
- A bit less than half glass of oil (125 ml=95 g; olive gives a slightly fruity flavor)
- any extras: nuts, hazelnuts, almonds, raisins, chocolate chips, apple, pineapple (if canned, use the syrup for the dought and when done!), berries!
Beat the eggs; mix in milk, oil, sugar, flour, baking powder, zest. Can be done unceremoniously and in a hurry, but will grow up better if the egg whites are beaten first, then the yolks, then the liquids and finally the solids.
Yields about 1.5 kg of dough, which is enough for a rather big baking bowl and still save some for about 20 muffins of 20g each; the dough stays perfectly on the fridge for some days, or even frozen.
Cook for 8 minutes in a 750 W microwave oven; check with a toothpick for doneness. Using less than 100% power doesn´t look like a good idea, since the dough will collapse during the pauses.
The dough will grow 2x or a bit more during cooking. Beware, the borders will look cooked sooner than the center, and the top sooner than the bottom. Don't care to try to use grill, brings more problems than is worth.
Freezes perfectly and goes nicely with coffee and such.
There are other interesting variations (yoghurt, wine, beer, ...). To be continued.