It depends mostly on three things:
1.) The size of your casserole
2.) Its temperature
3.) Your microwave oven's power setting and output
Notably, the microwave oven at my office is wimpy compared to the one at home. If frijoles take 30 seconds to heat up at home, they might take 2 minutes at work.
In the same way, it's like asking how long something takes to warm up on the stove. We don't know. Stoves have different performance characteristics.
2 Comments
1.) The size of your casserole
2.) Its temperature
3.) Your microwave oven's power setting and output
Notably, the microwave oven at my office is wimpy compared to the one at home. If frijoles take 30 seconds to heat up at home, they might take 2 minutes at work.
In the same way, it's like asking how long something takes to warm up on the stove. We don't know. Stoves have different performance characteristics.
Anyhow, just heat it up to your liking.
Good luck.