Not much, unless it’s a very fancy sandwich with lots of different toppings on - but I don’t think it ever replaces the base of butter on bread.
Apart from sandwiches a typical use of mayo may however be mixed with sour cream in a dressing to go with fried fish or cold sliced meat.
I have done butter and mayo before when I was a kid for bologna sandwiches.
I think I haven’t done mayo with sour cream for fried fish. That is usually tartar sauce which is what mayo, dill pickle and cream of tartar. or just lemon juice works. I have had fruit salads with like apples, grapes and cherries with sour cream and mayo dressing.
And of course ranch dressing which is like the midwest US go to for salad dressing for everything is mayonnaise based. blended with buttermilk, sour cream, and herbs like dill, chives, garlic, and onion. It is used as salad dressing, but also for a vegetable dip, or for dipping sauce for pretty much everything. It is kind of like a mayonnaise, sour cream or even ketchup replacement.
I meant to ask you, do they spray grains with any chemicals over there? Here most all grains are sprayed with glysophate(round-up) as a drying agent before harvest.
After some investigation I found out glyphosate is allowed before sawing and after harvest to kill weed, but not as a drying agent. But who knows…what’s not allowed is one thing…
They spray grass like wheat, barley, and maybe canola, with roundup pre-harvest about 3 weeks before harvest so it all dies at the same time and thus dries on the stalk so it is all ready to harvest at the same time. Otherwise part of the field might not be ready for harvest when other part may be ready.