Preheat oven to 400°F.
On a baking sheet, toss tomatoes with 1 turn of the pan of EVOO, salt and ground black pepper. Transfer to oven and roast for about 15 minutes, until popped and flattened a little. Remove and toss into a medium-size mixing bowl. Turn oven down to 250ºF.
While the tomatoes are roasting, cook the bacon in a medium skillet over medium-high heat until crisp. Remove and drain on a paper towel-lined plate then toss into the bowl with the tomatoes. Add the leeks to the skillet with the bacon drippings and cook for about 3-4 minutes, until tender. Add the leeks to the bowl with the bacon and tomatoes and toss everything together.