Preheat the oven to 300 degrees F. Cut tomatoes into 1/8-inch slices. Add to a bowl and toss with olive oil and garlic. Add salt & pepper to taste. Spread out evenly onto baking sheet with lip or baking pans. Roast for 1 hour then set aside.
On a well floured surface. roll dough into a 12-inch circle.
Spread tomatoes onto dough leaving a 2-inch border. Fold edges over (the dough will only partially cover the tomatoes.)
Sprinkle with thyme leaves (and cheese if desired.) Place crostata onto parchment paper on a cookie sheet.
Bake at 400 degrees for 25-30 minutes or until crust is lightly golden brown.