No hopeless, Just leave it empty of you don't have anything to put in there.

Remove the shelves and use it for cookie sheets?

As grover says not much better than that.

The narrow cabinet, yes, you can basically only use it for the size it is. But you can always get one of those sliding shelves and pull the cookie sheets out so you are not digging around in a narrow gap.

It sounds, though, like you want to be able to make use of all the available space, the gap in the corner that is blocked. It may cost you a couple hundred dollars, but if you have the skill and the vision. There is a solution.

Turn the drawers into a cabinet.

You can use one of the cabinet doors from a different location (turn that into a trendy open view cabinet) and insert one of those dead zone cabinets that get pulled out. Or even just a pull out lazy susan.

Good luck and let us know how it goes!