Prepare the tomatoes - Wash the tomatoes and slice each lengthwise. Use your finger to fish out the seeds and pulp, and discard (or compost). With a paring knife, trim the stem end from each tomato half. The arrange the tomatoes cut side up on a lined baking sheet.
Preheat the oven and prepare the marinade - Preheat the oven to 250 degrees, convection roast setting. In a small bowl, combine the oil, salt, basil, oregano and pepper.
Dress the tomatoes - Drizzle a few drops of the balsamic glaze in each of the tomato halves, then spoon a bit of the marinade in each as well.
Roast the tomatoes - Roast for about 2 hours, or until the tomatoes are soft and jammy. These are best serve warm or at room temperature.
Notes
I buy balsamic glaze at BJs, but you could make your own, or even substitute the balsamic with a sprinkling of sugar for prettier results. You're just trying to bring out the sweetness of the tomato.