Hello, for a few days I have learned to make a cake "from the microwave" (a popular recipe on the Internet). Until now, I did it in a mug, but I would like to make something square like a normal dough and then pour jelly. And here comes the question. Can I use a cardboard box as a cookie cutter? Such a brown-gray or a mold made of a technical block? Can you microwave paper at all? Because I don't have such a square vessel. Thank you in advance for your answer.
the cake came out great 
