Hershey's Brownie in a Mug Teacher Gift

My husband was given a brownie in a mug teacher gift at Christmas and today I looked at it as I do all of his gifts from students and said,We have to try this because it expires in 5 days! I followed the instructions: add 2 Tbsp of milk and 2 Tbsp of oil. I stirred it with a fork and microwaved it for 50 seconds and voila. I felt compelled to dump it out onto a plate as the mug looked too messy. It was a nicer presentation and tasted surprisingly good. So I immediately looked up a recipe for making one myself. https://preppykitchen.com/brownie-in-a-mug/