Cut off the tops of each tomato, scoop out the inside flesh, and sprinkl with 1/2 teaspoon salt. Turn upside down on a paper towel for 15 minutes.
To make breadcrumbs, preheat the oven to 375 degree. Add the bread slices to a food processor and pulse until it looks like large crumbs - about 8 pulses. Spread the breadcrumbs over a rimmed baking sheet and bake for 10 minutes or until they just begin to turn golden brown, tossing once or twice during baking.
Mix the toasted breadcrumbs, 1/4 cup of parmesan cheese, basil, 1/4 cup olive oil, and garlic cloves together in a large bowl.
Pat the tomatoes dry. Place cut side up in a lightly greased 9 by 13 inch baking dish. Divide the mixture amongst the hollowed tomatoes, approximately 1/4 cup per tomato. Drizzle about a teaspoon of olive oil on each tomato and top with the reaming 1/4 cup parmesan cheese. Bake for 20 minutes or until the cheese just begins to melt and bubble.