I unpacked an odd ironstone dish

when I was sorting in the rental. I bought the dish years ago, before the Internet I brought it home and last evening did Google lens searches to get an idea of values. This dish was elusive. It is marked Hall China, which made a lot of ironstone for over 100 years. I was looking for a deep saucer, or a soup cup underplate. In my search, I saw dishes that were called chunky butter pats. Not this dish, but it added an idea to my search. I posted the pictures I had taken on the FB group What is this? Antique, Vintage and Unusual Item Identification. I went back to searching, had one more idea, and found a dish identical in shape.

It is on Etsy and describes the dish as a butter dish for National Whipped Butter. The one for sale has a red glazed rim. The one I have is all white. I'm tickled my search led me to an id. Now, I want to find out more about National Whipped Butter, such as when it was made, and maybe see if this dish was a premium for families, or for businesses.

Doing research like this takes me mind off the woes in the world. Sort of like ancient history