Preheat oven to 400F. Line a large baking sheet with parchment paper or foil. Toss 2 550-mL containers grape tomatoes with 1 tbsp olive oil, 2 tsp brown sugar and 1/4 tsp salt. Season with pepper. Scatter tomatoes on prepared sheet. Roast in centre of oven, shaking pan halfway through, until tomatoes are soft and golden brown, about 20 min.