Curious Bread Shaped Carved Soapstone Slab (Warming Stone for Toasty Toast?)

I found this at an antiques show in New Hampshire--neither the dealer nor I had seen another like it, and neither of us was certain of its purpose. With old scald marks on it, though, surely it was made for heating--I personally like the idea that it was custom made for keeping the buttered toast (or grilled cheese sandwich!) warm! (I also really like the embedded pun--a toasty piece of toast!) Maybe more likely a pocket warmer  for a large pocket or to fit inside a cover and warm the bed...but there are knife marks on it too... Whatever the case a pretty excellent object I think!

 4 3/4" x 3 5/8" x 11/16", nice and heavy, with a super patina.