Warm a glass of water in the microwave for 2 minutes until the water is hot. Alternatively, if you want to do this on the stovetop, you can pour boiling water into the cup and let it sit for 30 seconds.
Pour the water into the sink to discard.
Place the glass upside down over a wrapped stick of butter.
Allow to sit for 10 minutes. The heat from the cup will soften the butter.
The Bowl Method
Add 2 cups of water to a bowl and microwave for 2 minutes. Alternatively, if you want to do this on the stovetop, you can pour boiling water into the bowl and let it sit for 30 seconds.
While the water is sitting in the bowl, cut the butter into slices and place them in a single layer on a plate that is smaller than the bowl.
Pour the water down the drain to discard the water.
Turn the bowl upside down over the plate and allow it to sit for 10 minutes. The heat from the bowl will soften the butter!