Preheat the oven to 400ºF and set the rack to the middle position.
With a serrated knife, cut about 1/2 inch off the top of each tomato. Core the tomatoes. Use a paring knife to cut around the outside edge and with a spoon or a serrated grapefruit spoon, scoop out the pulp and seeds. Reserve and chop the pulp to add to the stuffing.
Sprinkle the tomatoes with a generous pinch of salt and set them upside down in a colander to drain. off any juice
Prepare the stuffing. Heat the olive oil in a saute pan over medium high heat. Add the onions and chopped tomato pulp and saute for about 3 minutes or until the onions start to turn golden and any juice from the tomatoes has evaporated.
Add the garlic and saute for another 30 seconds. Add the remainder of the salt (or to taste), pepper, and oregano and stir to combine the seasonings.
Turn off the heat and add the bread crumbs, rice, Parmesan cheese, and about 2 tablespoons of basil. Stir well to combine.
Stuff each tomato with one-quarter of the stuffing mixture. Place the tomatoes in an 8 x 8-inch baking pan or casserole dish and drizzle each one with a little bit of olive oil. Cover lightly with foil. Bake for 15-20 minutes or until the tomatoes are softened and the stuffing is golden. Remove the foil for the last 5 minutes to allow the stuffing to brown and get crispy.
Sprinkle the remaining basil over the tomatoes once you remove them from the oven. Serve hot, warm, or at room temperature.
Notes
If you have trouble coring your tomato, insert a fork into the top of the core and twist it to break the bottom of the core free.You can use store-bought or homemade bread crumbs, but I prefer homemade ones. Tear 2-3 pieces or whole grain bread into small pieces to make them. Toast them for about 30 seconds under the broiler. Store leftover bread crumbs in a freezer bag in the freezer.Store leftovers in the refrigerator for up to 2 days. Reheat in a 350ºF oven for about 20 minutes or until warm.If prepping these ahead for your freezer, stuff, but don't bake them. Wrap each stuffed tomato in plastic wrap and place them in a freezer-safe container for up to 3 months. Thaw in the refrigerator before baking.