I got an idea for a restaurant or food truck! I can do

Often an idea can lead you to investigate and you might find another product to makes and sell. A truck or restaurant take a bit of capital and a lot of risk.
I do not where you live or the population around you. But as you can cook at home. Maybe a start would be to try and market this to those around you.
Can you get some free advertising - put up posters or hand out flyers. A Facebook page. Do you need to look at local codes and regulations.
It is always going to be difficult to establish your costs for say 20 portions or 100 portions. The ingredients your time, power costs and all. even taxes might apply. Do you have some people - friends who would help out free at least to start with. Lots to think about -

But why not start with that thinking and see how it goes.

That’s how small businesses start…with a good idea of something unique

@scabs Great - now I wonder this - could they allow to use thier kitchen to make your food. They can maybe help with supplies or know a supplier, You have to buy at the lowest cost.

When would people typically buy shibuya honey toast, as a treat say
How long after making it - does it last for - looking good.

Is there something else you could add in later - concentrate on the shibuya honey toast at the start then add another, so one week the toast is made and ready then the next another item. Maybe an item that uses some of the same ingredients.

Good luck.