Decrypting a Broccoli recipe

So my mother in laws boyfriend makes this brocolli. He steams broccoli and then dumps them in a dish and pours this this honey mustard like sauce on top of it then puts some shredded cheese on top and bakes it. He always brings the sauce over premade in a glass jar.

Here is the ingredients that I see and taste:

-Medium Cheddar Cheese
-maybe mayonaise?

Any idea what it is that he is making?

Its really good but I have no clue what it could be.

BTW the vinegar taste is quite dominant and I believe he uses bacon too. Man I’m getting hungry.