Step 1

Preheat the oven. Preheat the oven to 375 F. Lightly coat the bottom of an 8- or 9-inch square baking dish with olive oil.

Step 2

Hollow out the tomatoes. Use a serrated knife to cut off the tops of the tomatoes. You can discard them or save them to use as a lid. Use a spoon to scoop out the flesh. Roughly chop the scooped-out flesh, and transfer it, along with any liquid on the cutting board, into a small bowl for the filling.

Step 3

Salt the tomatoes. Add a small pinch (1/8 teaspoon) to the inside of each tomato. Set the tomatoes upside down to drain on a plate while you prepare the filling.

Step 4

Saute the alliums. In a large nonstick skillet, heat the olive oil over medium heat. Add the onion and cook, stirring occasionally with a wooden spoon, until softened and translucent, about 10 minutes. Stir in the garlic and cook until fragrant, about 30 seconds.

Step 5

Reduce the tomato juice. Pour in the reserved tomato flesh and and juice. Season with the remaining 1/2 teaspoon of salt. Continue to cook, undisturbed, until almost all of the liquid has evaporated, about 5 minutes.

Step 6

Finish the filling. Take the pan off the heat and add the tuna, olives, parsley, and lemon juice. Season to taste with freshly ground black pepper.

Step 7

Stuff the tomatoes. Place the tomatoes, evenly spaced, in the greased baking dish. Divide the filling equally among the tomatoes, mounding the tops. If you saved the top of the tomatoes, you can set them on top of the filling.

Step 8

Bake. Bake for 30 minutes, or until the tomatoes are tender.

Step 9

Serve. Serve warm, room temperature, or cold.