"and" with meals - eating separately or together

Question

I have toast and jam for breakfast.

Does it mean that I eat toast and jam separately or together with spread jam on toast?

What about other examples? Does "and" mean separately or together as if combined?

I have cereal and milk for for breakfast.

I have fish and potatoes for dinner.

Edit: I've edited some examples and added new. I need some clarification.

What about bread and butter?

I have bread and butter for breakfast.

or

I have pastries and milk.

Does it mean here mixed or separate? I mean I first eat pastries, then milk or eat them together?

Can I replace "and" with "with" without a difference in meaning?

Answer 1

Generally speaking: and doesn't mean mixing them up together. It only means as well or in addition to. For example, I can say:

Yesterday I ate some fruits and vegetables.

It doesn't even mean that I ate them in the same meal, let alone being mixed together. It only means that I ate both.

Although depending on the context it may mean mixing up together, but to make sure you had them together in a single sentence, you may say:

I have toast with jam.

I'm having fish along with potatoes.

Answer 2

This is much more about common sense than about grammar. If I say I'm having toast and jam, you naturally assume the jam is spread on the toast, because that is common practice. In the same way, tea and biscuits is separate, because that's how most people consume them.

Unless you're completely unfamiliar with the food mentioned, just use your best judgement. Otherwise you have to ask. For example if say in Japan they have a dish called "Ochazuke" which is tea and rice (and other things), you might have to ask for details or look it up on Google.

(FYI it's like a soup of green tea over rice. Very nice, especially in cold weather.)