In a small saucepan over low heat, COOK butter and chocolate until melted, STIRRING often.
With an electric mixer, BEAT eggs at medium speed for 5 minutes; gradually ADD sugar, BEATING until blended; gradually ADD chocolate mixture, flour and vanilla, BEATING until blended; STIR in 1/2 cup pecans.
Lightly GREASE 9-inch pie pan; POUR in mixture.
BAKE at 350° until center is firm, about 35 - 40 minutes; COOL.
TOP each serving with vanilla ice cream and chocolate syrup; SPRINKLE with remaining chopped pecans.
Per Serving (excluding unknown items): 646 Calories; 40g Fat (53.2% calories from fat); 8g Protein; 71g Carbohydrate; 3g Dietary Fiber; 155mg Cholesterol; 260mg Sodium. Exchanges: 1 Grain(Starch); 1/2 Lean Meat; 7 1/2 Fat; 4 Other Carbohydrates.