I love Mid Century Modern (MCM) and this is a classic MCM look!! Very cool!!!
I can see why you are puzzled. Me too!! When I first saw it, I was like, oh, cool, that is the Mardi Gras pattern, but when I blew it up on the big screen it is similar but not a match.
You could try to send it to Replacements.Com and see if they can tell you what you have. If you took a picture of the plate without the cup in the center and had it clear, you can try their photo match software yourself. I tried altering you photo to do that, but it is too dark and came up not recognizable.
Post back what you learn!! I am so curious!!