I forgot to take the butter from the fridge to mix for cake. What is the best way to bring it to room temperature and soften it quickly?
When making a cake it is best if all of the ingredients are at room temperature as this will help them to combine more easily. In particular, if you have to cream butter and sugar then the butter needs to be soft enough to beat. If you have fridge-cold butter then the easiest way to soften it is to cut it into very thin slices. Spread these slices out in a single layer over a large plate or chopping board and let it stand, preferably in a warm place, for about 15 minutes. It should then be soft enough to beat.
You can microwave the butter slices but you have to do this extremely carefully as we find that some of the butter tends to melt around the edges when it is microwaved. If your eggs are also fridge cold then you can immerse them in a bowl of warm water for 10 minutes to help them to come up to room temperature.
Alternatively, you could instead make a cake that uses melted butter, such as one of Ningella's gingerbread recipes, or the Baby Bundt Cakes from Domestic Goddess.