Heat oven to 400°F. Place the cherry tomatoes on a baking sheet and toss with 2 teaspoons olive oil, 1/4 teaspoon kosher salt, and a few grinds of black pepper. Roast, tossing occasionally, until they begin to burst, 20 to 25 minutes. Set aside.
Rub each baguette slice with the garlic clove and place a slice of brie on top. Place on a baking sheet and heat in a 400°F oven until the brie begins to melt, 3 to 4 minutes.
Remove and top each with one of the roasted cherry tomatoes. Drizzle evenly with 1 tablespoon of olive oil.