Preheat oven to 425 F.Cut roma tomatoes in half lengthwise (no need to remove the stem bit). Place in a large roasting pan (mine is 11x16-inches and a couple of inches deep.) Scatter garlic over-top. Drizzle with olive oil and balsamic vinegar. Sprinkle with oregano, basil, salt and pepper. Toss with a large spoon to coat.
Place in preheated oven for 60-70 minutes, stirring well half way through cooking. The mixture shouldn't dry out completely and some of the tomato skins will char slightly. Stirring well half way through ensures that nothing gets too dark. Allow to cool.
Remove tomatoes from pan (if there is a lot of liquid in the pan, use a slotted spoon to remove, leaving most of the liquid behind). Blend in a food processor or use immersion blender to create a sauce with your desired chunkiness level. If I'm making a large batch, I tend to do a few smooth and leave a few chunkier.