Heat oil in large skillet over medium heat. Cook Swiss chard, onion, garlic, salt and hot pepper flakes about 10 min., or until onions are soft and Swiss chard is wilted. Remove from heat to cool completely.
Meanwhile, preheat oven to 200°C (400°F). Mix ricotta, 1 egg, honey, lemon zest and lemon juice into Swiss chard mixture. Fold in Brie cubes.
Place pie crust on parchment-lined baking sheet. Spread filling onto pie crust, leaving 2 in. (5 cm) border around the edge. Fold pie crust border over the edge of the filling, making several small tucks, to shape into a round, rustic pie. Beat remaining egg with 1 tbsp (15 mL) water; brush onto border.
Bake on lowest rack 30 min., or until pie crust is golden brown and filling is set. (Make-Ahead: Pie can be baked up to 1 day in advance, cooled, covered and kept chilled. Reheat in 180°C (350°F) oven about 25 min., or until hot. Serve warm or at room temperature. Cut into small wedges as an appetizer or serve for lunch with a fresh green salad.