This was written for ProvocativeMolotov who prompted me to write a Sherlock/Harry Potter crossover where Mycroft's patronus is a cake.

There was pride in Harry's eyes as he looked around the room of requirement. He wasn't surprised to see that Sherlock was amongst the first to master the Patronus spell. The quiet Slytherin was one of his most talented students. Now his otter was floating around him. Hermione had also mastered the spell and, just like Sherlock, her patronus had taken the form of an otter.

Other students had more difficulties. Although he had managed to get some white smoke to come out of his wand, John still had some difficulties. Harry walked towards the fellow Gryffindor and corrected his posture. Soon he managed to conjure a corporeal patronus in the form of a hedgehog.

Molly Hooper, a shy Hufflepuff girl, looked rather disappointed when her patronus, a kitten, disappeared after a second.

„Don't stop thinking about your happy memory, even once your patronus takes form. If you do, it will vanish." Molly nodded and tried again. This time her patronus lasted slightly longer, for about 5 seconds. Harry gave her an encouraging smile. Then he continued to walk around, now and then giving some advice or correcting the posture.

When he reached Mycroft, he was surprised to see that he hadn't conjured a patronus yet. The Ravenclaw was usually one of the first people to successfully cast a new spell, along with Hermione and his brother Sherlock.

„What's wrong, Mycroft?" Harry asked. Mycroft sighed.

„I simply cannot remember a truly happy event!" he said, despair in his voice. Harry thought for a moment.

„What do you like to do? Do you have any hobbies?" he asked. Mycroft's eyes lit up.

„Eating!"

„Well, then try to remember a time when you ate something especially tasty." Harry suggested. Mycroft nodded and closed his eyes. When he opened them again, determination was on his face. He lifted his wand and shouted „Expecto Patronum!".

White light burst from the tip of his wand and quickly gained form. For a second, Harry thought that he was imagining it. But there was no doubt. Mycroft's patronus was a... cake?