Preheat oven to 350 degrees F. Place 3 of the chocolate squares and the butter in large microwaveable bowl. Microwave on HIGH 2 minutes or until butter is melted. Stir until chocolate is completely melted.
Stir in sugar and vanilla until well blended. Add eggs, 1 at a time, beating with electric mixer on low speed after each addition until well blended. Add 1/4 cup of the flour and the baking soda; mix well. Add remaining 1 cup flour alternately with the water, beating until well blended after each addition. Pour evenly into 9-inch round cake pan sprayed with cooking spray.
Bake 30 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes; remove from pan to wire rack. Cool completely. Top with the whipped topping and strawberries just before serving. Melt remaining 2 chocolate squares as directed on package; drizzle over cake. Let stand until chocolate is set. Store in refrigerator.
In a mixing bowl, combine the first five ingredients. Add the water, oil, vinegar and vanilla. Beat on low speed for 1 minute. Beat on medium for 1 minute. Pour into a greased 13-in. x 9-in. x 2-in. baking pan. Bake at 350 degrees F for 40-45 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack.
For frosting, in a mixing bowl, beat the milk and pudding mix for 2 minutes. Beat in whipped topping. Spread over cake. Refrigerate leftovers.