A lot of recipes, mostly baking recipes, call for room temperature butter to be used. If you remember to take your butter out of the fridge a few hours, or the night before, then that is normally the best way. However, if you forget, or if the weather is particularly hot, it is good to have a quick way to get fridge-cold butter to room temperature, pretty quickly.
The best way to soften butter:
The best way to do this is to chop the butter into small pieces or thin slices and leave to sit at room temperature until it warms up. I allow around half an hour but in the summer, 15 minutes may be long enough.
After the butter has softened, beat it with an electric whisk until light and fluffy. The butter is now ready to use.
You can also soften butter in the microwave:
If you really do not have time to wait for 15 – 30 minutes, you can soften butter in the microwave. However, you have to very careful not to actually melt the butter, even just a little bit. Melted butter does not bond properly with sugar when you are beating it and you may end up with cookies that spread too much, and cakes and muffins which are flat and dense.
If you really have to use the microwave, chop it into cubes and microwave in 5 second bursts, stirring the butter in between each burst, until you achieve the consistency you are looking for.