Place the flour and salt in a food pro cessor. Pulse to combine. Add the butter, pulse until mixture resembles a coarse meal. With the motor running, slowly pour in 3 tbsp (45 mL) ice-cold water until dough forms a ball. Remove dough from processor and shape into a disk. Wrap in plastic wrap and chill at least 60 min. or up to 24 hr.
Lightly flour work surface. Roll pastry to 14-in. (35-cm) round, dusting work surface with more flour as needed. Transfer to baking sheet lined with parchment paper. Prick all over with fork.
Toss peaches, with honey, sugar and thyme. Stir in cornstarch. Arrange over top of pastry, leaving a 2-in.(5-cm) border. Fold over the pastry border to form a crust. Scatter Brie cubes over filling.
Bake on lowest rack of oven preheated to 425°F (220°C), for 20 to 25 min. or until pastry is golden brown and juices are bubbling. Cut into slices and serve warm or at room temperature.