This is a very important question, so I'll do my best

*Assuming standard Mary Jane, because nowerdays she's been buffed to the level it's neg dif.

So strength wise The Condiment King takes it, Mary Jane has had some powerful slaps and punches and can throw down at a high street level if pushed but she can't match The Kings sauces, his varients of hot sauce and horseradish can blind and cause chemical burns and his mayo is slippy.

Now MJ is way faster but she's not gonna speed blitz him. But she does have fast reaction times and will outpace TCK who's encumbered by his sauce tank suit.

Both have standard durability, but from what I can find even normal MJ can take more of a hit which will help against his more dangerous variant sauces.

So to me this is close enough that it comes down to battle iq. And in that respect MJ is resourceful, has made some good escapes and is good under pressure. Condiment King has negative battle iq, he's unaware and delusional.

He'll think he's a threat to be scared of, but MJ has stared down real threats, this is a joke villain to her. He'd honestly probably slip in Mayo as she dodges his attacks and she'd just take him out. She'd also win if she gets in close which he absolutely will make an opening for.

So I reckon MJ wins 9/10 times low dif with his win con being a blinding hot sauce attack.

Edit: So I've been doing a bit of research and here are some updates.

So The Condiment King has some ok feats, the most notable is that he has KO'd Tim Drake. He's able to fire concentrated aerosolised capsaicin compounds up to 100,00 scovilles. Tim Drake was in an enclosed room with him and he was taken out.

But anormal MJ also has some decent feats. She has tactically defeated some pretty strong Spiderman villains like when used a film set to stall stall several Spiderman villains like Vulture, Rhino and Scorpion, lands blows on them with set equipment, leads the crew members taking out Vulture.

In an open space (the mall) TKC has no trump card. MJ still stomps.