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It's two sandwiches...topologically speaking.
If you take the traditional idea of a sandwich and draw a loop around the plane where the surfaces come together you get a mathematical sandwich.
Since the bagel abomination has two such areas and you can draw non-intersecting loops around each, it follows that there are indeed two sandwiches present.
That depends on your definition of a sandwichable surface. If crust can be buttered as well and is considered equal to cut surfaces (which, coming from a rye bread country, is certainly the case with these fluffy things), then this is simply a sandwich without filling in the middle. This might also be achieved by suboptimal spreading on a single surface.
I'm pretty sure it counts as a sandwich as defined by the ham sandwich theorem. The only part that might be debatable is that the filling is not a single connected volume, but that doesn't seem to be required by the proof.