This recipe comes from "Simply Seafood", a magazine published in Seattle in the late 70's-early 90's. Sadly, no longer in existence, it was one of the best sources of fish & seafood recipes, as well as the state of the fish industry.
I've been unable to find a similar authentic recipe in any of my cookbooks, magazines, etc. I have spoken to Maltese friends who confirm the authenticity of the recipe.
Maltese cuisine is influenced by Africa and, in this case, Italy. Clearly, fish and seafood play a key role in the regular meals of this island.
The beauty of this recipe is that while it is described as baking, the dish starts with a relatively small amount of liquid and the tomatoes give up liquid as they soften and melt at the relatively low cooking temperature. Thus, this is more a braise than a bake and the fish retains or absorbs liquid as it cooks, thus staying moist. This is a very different style of tuna compared to the quick, high heat, "seared on the outside, rare on the inside" style.
This recipe is quite forgiving: I have used frozen tuna steaks without defrosting them and cooked this in a slow cooker at low heat for 6 hours or at high heat for 4 hours: just add enough additional water so that the tuna stays moist. Also, if you're blessed with thick tuna steaks, whether baking or using a slow cooker, just add water as needed and keep the tuna moist until it cooks through ...
Serve with a green salad and crusty bread. Wine along with the meal (or if you choose, added to the braising liquid) is a wonderful touch -- for the broth, you can use either white or red. For drinking, a Sicilian wine would match the Mediterranean island origin of the dish, but anything from southern Italy would be appropriate ...
In additon to being a dinner, any leftovers can be served at room temperature or heated up for lunch ...
Note that since the salt and pepper are "to taste", the nutritional analysis for sodium will be incorrect -- if you are on a no/low/restricted salt diet, beware!!