I don't really understand what you want to do. I'm guessing you deliberately chose the simplest possible example, and that what you really want to do is more complicated. But since your example is trivially
@(x) x + 2
I can't quite get what you really need.
Maybe you mean something like this?
y = @(z) z + 1; % The intermediate function?
f = @(x,g) x + g; % The final function
f(1,y(1)) % Calling syntax
