Half tomatoes and place in a medium-size bowl. Sprinkle with ½ teaspoon salt and stir gently, then transfer tomatoes to a strainer and let drain for 30 minutes (this will help release some of the moisture from the tomatoes which will help them roast quicker). After 30 minutes, pat off any excess moisture with paper towels and return tomatoes to bowl.
Combine balsamic vinegar, olive oil, Italian seasoning, garlic salt, pepper, and red pepper flakes in a small bowl. Drizzle over tomatoes and stir gently to combine. Transfer tomatoes to the prepared sheet pan. (Be sure to scrape all the good spice/oil mixture onto the sheet pan with the tomatoes.)
* Use any combination of herbs you have available. I really like using a combination of equal parts rosemary, parsley and basil but thyme, chives and/or oregano are also wonderful.