Preparation Preheat oven to 350°F. Butter and flour 15 1/2x10 1/2x1-inch baking sheet. Whisk sugar, flour, baking soda and salt in large bowl to blend. Whisk milk, butter and cocoa powder in heavy medium saucepan over medium heat just until butter melts and mixture is smooth. Remove saucepan from heat. Whisk cocoa mixture, then eggs and vanilla into dry ingredients. Spread batter in prepared pan and sprinkle with 1 cup chocolate chips. Bake cake until tester inserted into center comes out clean, about 25 minutes. Arrange toasted pecans atop cake. Cool cake in pan. Meanwhile, bring whipping cream and corn syrup to simmer in heavy medium saucepan. Add remaining 1 1/3 cups chocolate chips. Whisk until chocolate chips have melted and glaze is smooth. Cool glaze 15 minutes. Pour glaze evenly over cake. Chill at least 1 hour and up to 2 days.
Preparation Preheat oven to 350°F. Butter and flour 15 1/2x10 1/2x1-inch baking sheet. Whisk sugar, flour, baking soda and salt in large bowl to blend. Whisk milk, butter and cocoa powder in heavy medium saucepan over medium heat just until butter melts and mixture is smooth. Remove saucepan from heat. Whisk cocoa mixture, then eggs and vanilla into dry ingredients. Spread batter in prepared pan and sprinkle with 1 cup chocolate chips. Bake cake until tester inserted into center comes out clean, about 25 minutes. Arrange toasted pecans atop cake. Cool cake in pan. Meanwhile, bring whipping cream and corn syrup to simmer in heavy medium saucepan. Add remaining 1 1/3 cups chocolate chips. Whisk until chocolate chips have melted and glaze is smooth. Cool glaze 15 minutes. Pour glaze evenly over cake. Chill at least 1 hour and up to 2 days.