A good balsamic vinegar makes all the difference in the roasted tomatoes, whose heat will immediately melt the soft Brie. There's no need to cut the rind off the Brie, since it's edible.
1 teaspoon olive oil
2 cups halved cherry tomatoes (about 1 pound)
2 tablespoons balsamic vinegar
1 tablespoon chopped fresh thyme
1/4 teaspoon kosher salt
1/8 teaspoon black pepper
1/4 cup low-fat mayonnaise
1 tablespoon whole-grain Dijon mustard
1 garlic clove, minced
1 (16-ounce) loaf French bread, cut in half horizontally
3 ounces Brie cheese, sliced
3 cups shredded cooked chicken breast (about 1 pound)
2 teaspoons extra-virgin olive oil
1 teaspoon balsamic vinegar
1/8 teaspoon kosher salt
2 cups fresh spinach
How to Make It
Preheat oven to 300°.
Heat 1 teaspoon oil in a large nonstick skillet over medium-high heat. Add tomatoes; cook 4 minutes, stirring once. Remove from heat; stir in 2 tablespoons vinegar. Sprinkle tomatoes with thyme, 1/4 teaspoon salt, and pepper. Wrap handle of pan with foil; bake at 300° for 15 minutes. Keep warm.
Combine mayonnaise, mustard, and garlic in a small bowl. Spread mayonnaise mixture evenly over top half of bread loaf. Spoon tomatoes evenly over bottom half of loaf. Arrange Brie over tomatoes; top with chicken. Combine 2 teaspoons oil, 1 teaspoon vinegar, and 1/8 teaspoon salt in a medium bowl, stirring with a whisk. Add spinach, tossing gently to coat. Top chicken with spinach mixture; replace top half of bread. Cut loaf into 6 pieces.