Pour the milk into a microwave-safe bowl and heat in 1 minute increments until the temperature of the milk reaches 180 degrees.* Stir between each time interval to distribute the heat. Depending on the bowl and microwave you use, this will take about 5 minutes. Be sure not to let the milk boil.
Carefully place the pan into the preheated oven and bake for 35-40 minutes. The exact time may depend on the size and shape of the ramekins you use. The custard is done when you insert a knife into the center of a cup and it comes out clean.
*This is called “scalding” the milk. Many old recipes call for this process. It is not necessary to do this for safety reasons any longer due to the pasteurization process. However, scalded milk does give the custard a little bit of a smoother texture, so I do recommend taking the time to scald the milk. You can also do this on the stovetop instead of the microwave.
**This is called “tempering” the eggs. Be sure to drizzle the hot milk slowly and constantly whisk (or use a hand mixer beating on medium speed the entire time you are drizzling) so that the hot milk doesn’t cook the eggs.