"on the side" means, 99 44/100% of the time, that you want to have a restaurant dish prepared for you in a slightly different way, or actually, not prepared to completion at all.
Most often used with reference to sauces, one might ask for them on the side because you don't want to use as much as they would put on, or perhaps you like to dip rather than having it mixed in, or you want it on some of the dish but not all of it, or any other reason that suits you. (French fries are always served with ketchup on the side, but some people squirt it all over. That's how you can tell they're aliens.)
"on the side" was a funny device used in the 1989 movie When Harry Met Sally, starring Billy Crystal and Meg Ryan. Firstly in a cafe they stopped at during their post-college road trip.
Harry: I'll have a #3.
Sally: I'd like the chef salad, please, with oil and vinegar on the side, and apple pie à la mode.
But I'd like the pie heated, and I don't want the ice cream on the top, I want it on the side.
And I'd like strawberry instead of vanilla if you have it; if not, then no ice cream, just whipped cream,
but only if it's real, if it's out of a can then nothing.
Waitress: Not even the pie?
Sally: No, just the pie, but then not heated.
Hopefully the waitress could safely assume that the whipped cream should be on top, but ... maybe on the side.
Years later, on the phone, Harry is describing the two types of women: high maintenance and low maintenance.
Sally: Which kind am I?
Harry: You're the worst kind, you're high maintenance but you think you're low maintenance.
Sally: I don't see that.
Harry: "Waiter, I'll begin with the house salad, but I don't want the regular dressing,
I'll have the balsamic vinegar and oil but on the side. Then I'll have the salmon
with the mustard sauce, but on the side."
"on the side" is a very big thing for you.
Side Quest 2024