For any of you veteran cooks out there, you might recognize this tomato and mozzarella "marinade." Yes, it's the Silver Palate recipe that is tossed with pasta to create a summer pasta dish that most of us probably enjoyed while growing up (except that one had Brie in it). My mom and I made the pasta recently and the memory still hangs vividly in my head because of a particular argument we had while making it. I wanted to "wing it" and throw the marinade together as I saw fit, and she was adamant about me finding the recipe online and sticking to it. I'm glad I let her win that battle, and let me just tell you, if you try to skirt the two hours of marinating, it just won't taste as good. There will be some leftover, too, so get that pasta water boiling.
In a large bowl, combine the tomatoes, basil, garlic, mozzarella cheese, salt, pepper, and 1 cup of the olive oil. Mix well, cover, and let sit at room temperature for 2 hours.
After 2 hours, prepare the grilled cheese. Lay the slices of sourdough out on a work surface. Take about ¼ cup of the oil from the marinated tomato mixture and combine with the remaining olive oil in a small bowl. Brush each slide of the sourdough bread with the olive oil mixture.
Heat a nonstick sauté pan over medium-high heat and add 1 slice of bread, oil side down. Cover the bread with 2 slices of the mozzarella cheese, or enough to cover the bread, and ½ cup of the marinated tomato mixture; be careful not to let it fall off the bread.
Cover the mixture with 2 more slices of mozzarella, and then a slice of sourdough, non-oiled side down. Cook, covered, until one side of the bread is toasted and golden brown, about 5 minutes. Flip the grilled cheese and cook until the other side is toasted, about 2-3 more minutes. Repeat with the remaining slices of bread.
Slice each grilled cheese in half before serving.