Preheat oven 250 degrees
Line large baking sheet with parchment paper.
Rinse cherry tomatoes in cold water, trim top and slice in half.
Place in medium mixing bowl with garlic, onion, vinegar, olive oil, salt & pepper to taste.
Mix well and spread out on baking sheet.
Slow roast 45-minutes-1 hour.
Place on serving tray or in bowl with fresh sliced mozzarella, basil and an additional drizzle of olive oil and balsamic vinegar.
Can be served alone or with gluten free bread, crackers, etc.