I was happy to discover that my guess was right; these tomatoes are quite well suited to stuffing. A firm sturdy structure held up well to cooking and there was plenty of room for the stuffing inside.
I did a pretty traditional Italian version for my first try. I cooked up a bit of sweet Italian sausage with onions and peppers, added some greens (spinach would be a little more standard, but the fresh braising blend was a much better choice than the frozen spinach I've got on hand. The frozen vegetables would have released a lot of juice and I wanted to keep the mix pretty dry. Once the greens were wilted I added fresh bread crumbs to soak up all the liquid in the pan. Finally, I mixed in a Romano cheese herb blend to add some more flavor and bind the stuffing together. (and salt and pepper to taste, of course)
I had hollowed the tomato making sure to get all the seed and liquid bits out and then rubbed a bit of salt around the inside for seasoning and to draw out a bit more liquid. I let the tomato rest in a bowl upside down so any juice released could drain out. I wasn't sure whether to pack the stuffing in tightly or loosely, but I had made far too much so tightly it was going to be. In retrospect there's nothing in there that was going to expand so there was no need to leave room. A bit of mozzarella on top and into a 325 degree oven for 15 minutes.
The results were, well, a cooked tomato with sausage, onions, peppers a bit of greens and some cheese. Not a watery mess, but nothing spectacular emerged either. A bit of broiling might have browned the tomato a bit and added a little more flavor. Oh, I also sprayed a bit of olive oil on the outside of the tomato and tossed on a bit of salt. It didn't make much difference in flavor (although it managed to make the presentation even more hideous. I mean, just look at that picture!), but if the tomato had started to cook down, I think it would have helped.
While I was putting this together, it occurred to me that tomatoes, onions and peppers have worked their way into most world cuisines so you could easily adjust the recipe to suit your mood. Use an appropriately spiced ground or chopped meat and rice or couscous or whatever local starch fits and there you go. If we keep getting these tomatoes, I think I'm going to trying out a few more variations.
My first inspiration along these lines was a breakfast stuffed tomato. I used the same onions and peppers although chopped a bit more finely this time along with some breakfast sausage. I seasoned this with what I consider a tragically ignored flavor combination: maple syrup and Tabasco sauce. I had hoped the reduced syrup would act as a binder, but I think the water in the hot sauce (actually another vinegar-based hot pepper sauce Cholula that adds some spices for a more well-rounded flavor) kept that from happening. So I threw in some of the colby jack cheese that I had shredded for a topping.
Once that was packed into the tomato, I cracked an egg on top, added the cheese and into the oven it went. Since the first tomato was pretty much just warmed through, I turned the heat up to 350 degrees this time. After 15 minutes the tomato was cooked, but the egg wasn't. I checked on baked eggs in my old Betty Crocker and 15 minutes at 350 is supposed to do the trick; I think the cheese over top insulated the egg from the heat. So I pushed the cheese aside and put the tomato back in for another five minutes. Here's the results. Not pretty, but it was tasty. Was it as tasty as everything grilled separately? Not really as it missed out the browning and all the flavors and textures it brings with it. But it was less of a mess, probably a little lower fat and an interesting presentation (if done correctly. I think my results ended up more "interesting" than interesting). That's the whole point of stuffing a tomato in the first place, but I don't know if it's worth what it loses in flavor.
I'll have to give a bit of thought on how to improve the results; I suspect broiling is going to be involved. Or possibly breading and deep frying. If you've got any ideas I'd like to hear them.
There's also the issue of the waste of all that tomato innards that were scooped out. I probably should have cooked a stuffed pepper at the same time and just moved the tomato bits over.