We found this odd pan at the family's summer cottage. The cottage is in Central Finland, and used to be a croft before my grandfather bought it. This thing has been on the edge of the stove for a while, and nobody seems to know what it is.
By the way the handle is pointing, the pan is supposed to be used convex side up. The convexity is about ten centimeters high, and has chevron-shaped ridges forming channels down the mound. It looks a bit like a lemon-squeezer from the side, but with a shallower slope. There's also a channel around the base of the mound, and a beak for pouring. The pan is about the size of my outstretched fingers, or a small frying pan. Here's a side view:
I tried a reverse image search and came up empty. The one guess anyone made is that it's a pan for melting fat, but I couldn't find an image of one of those on Google.