Making a new rear floor panel

Here is the car's floor panel. This is the panel for the rear, where the seats are placed.

For some years, this part, was full of water, and the oxide destroyed it. I must to make a new part. I think that is a posibility to make it, with a metal panel, or maybe buying a old tray oven and cut it and modify.
My first attempt is to take a metal panel and a hammer and make it.

Does anyone know another option?