Mango chutney and apple slices add some sweetness to the savory brie.
Heat a griddle or large cast-iron skillet over medium. In a small bowl, mix the mayonnaise and the ground coriander. Slather on one side of each slice of bread. Build sandwiches with the cheese, chutney, apple, onions, and bread, spread-side facing out. Cook, turning once, until the bread is toasted and the cheese is melted, about 3 minutes per side.