Heat oven to 350°F. Coat a 9-inch pie plate with nonstick spray.
Melt chocolate and butter in a small saucepan over low heat. Stir together eggs, sugar, flour and vanilla and add to chocolate mixture. Pour into prepared pie plate.
Combine sweetened condensed milk and coconut. Spoon over chocolate mixture leaving a 1/2- to 1-inch border. Bake at 350°F for 35 to 40 minutes, until center is firm but still a little moist. Cool completely on wire rack.