Put all the ingredients in a mug and stir well. You don't need to melt the Biscoff spread first. I like using a fork to mix everything.
Microwave it until the cake is set. My microwave oven is 1000 watts and it took 1 minute and 30 seconds.
Top with some whipped cream and some more Lotus Biscoff spread (or your favorite toppings), if desired.
Serve immediately.
Enjoy!
Notes
This recipe is based on my microwave oven which is 1000 watts and it took 1 ½ minutes. If your microwave is more than 1000 watts, you may need to reduce the cooking time by 20-30 seconds.