How would either MC or minister have no knowledge at all of each other? He was sous chef to the only level 100 chef in the world who happens to have a restaurant in the royal capital.
Even if she thought him beneath her notice, he should have been well aware of who she was and seen her at some point. Not to mention he was a top member of the most renown adventure guild, and just took out that guild's leader in addition to a judge and the head of a noble family.
Let's be honest, MC floats way too far under the radar, unnaturally so. It would be like if Gordan Ramsey was out slaying dragons when he wasn't in the kitchen. Everyone would know even with whatever suppression the silver-wings were doing with his reputation.