Preheat oven 450 degrees F.
For the baked stuffed tomatoes you need to make 4 tomato cups out of your 2 tomatoes. To do so, cut a very thin slice off both ends of each of the 2 tomatoes, this is to create 4 flat bottoms. Then cut each tomato in half across its circumference. You should have 4 cup shapes, using the thinly sliced side as the bottom of the cups. To create a cavity, use a melon ball scoop to remove the seeds and pulp from the wide, fleshy side of each tomato cup. You don't have to be too fussy about this. You are just trying to create enough room to hold the filling. When scooping take some care not to puncture through the bottoms of the cups. If you do puncture it, don't worry, it is not the end of the world, just keep moving forward. Season the inside of the tomato cavities with salt and pepper. Reserve the seasoned tomato cups while you make the filling.
In a small mixing bowl combine the ricotta cheese, lemon zest, cilantro, parsley, garlic, scallions, Parmigiano and season with salt and pepper. Taste the mixture. This is your last chance to adjust the seasoning. Once you're happy with the flavor, add the egg yolk and mix thoroughly. Divide the filling between the 4 tomato cup cavities, pushing it into the cavity with a rubber spatula or spoon. Drizzle some extra-virgin olive oil into a baking dish. Arrange your stuffed tomatoes in the dish, transfer to the hot oven, and bake for 15 to 17 minutes. The stuffing and the tomatoes should be fully cooked and the top should be lightly brown.