1. Heat oven to 200C/180C fan/gas 6 and heat a griddle pan over a medium heat Until very hot. Brush one side of each tortilla with a little of the olive oil. Place a tortilla in the pan, oiled-side down. Cook for 1 min until nicely marked, pressing down with a spatula. Repeat with the remaining tortillas.
2. Arrange half the tortillas on baking sheets, marked-side down. Place a layer of Brie on top, then scatter over the chilli, mango and spring onions. Season to taste.
3. Cover with the remaining tortillas, marked-side up, and bake for about 5 mins or until heated through and the Brie has melted. Allow the quesadillas to cool slightly for ease of handling, then cut each one into 8 wedges with a serrated knife, pizza cutter or kitchen scissors. Arrange on warmed plates or a large platter to serve.