Preheat oven to 350°F. Spray 9 in. round baking pans with vegetable pan spray.
In medium bowl, combine flour, baking soda and salt. In large microwavable bowl, melt chocolate and butter for 2 minutes or until butter is melted. (Mixture can also be melted on top of stove in heavy saucepan over low heat.) Stir until smooth. Transfer to large bowl; add sugar and beat with electric mixer until well blended. Add eggs, one at a time, and vanilla; mix well. Add flour mixture alternately with milk; beat until well blended and smooth. Pour into prepared pans.
Bake 32-36 minutes or until toothpick inserted in center comes out clean. Cool in pan 15 minutes. Remove to cooling grid; cool completely before decorating.