Generic typings for one property on an Interface in TypeScript

Question

I'm trying to type a method, that is part of an interface and I need it to take a generic. Below is a simplified example of what I want. I want users of the API be able to type method with a generic. However I don't know here to specify it.

Can anyone explain to me how to add generics to method on Main here? Without the generics being passed to the Main interface but to the actual method.

interface Method<T> {
  (t: T): T
}

interface Main {
  method: Method
}

const main: Main = {
  method: id => id,
}

main.method<string>('test')