CAKE: Preheat oven to 375 degrees. In a small saucepan, combine mint chocolate chips and 1/4 cup of water. Cook over medium heat, stirring constantly, until chips are melted and mixture is smooth. Cool 10 minutes.
In medium bowl, combine flour, salt, baking soda and baking powder, set aside.
In a large bowl, combine brown sugar and butter, beat until creamy. Add eggs one at a time, beating well after each addition. Blend in chocolate mixture. Gradually beat in flour mixture alternately with remaining 1 cup of water.
Pour into 2 greased and floured 9-inch round baking pans. Bake for 20 to 25 minutes, or until cakes test done. Cool completely on wire racks. Fill and frost with Chocolate Mint Frosting below.
CHOCOLATE MINT FROSTING: In a double boiler over hot (not boiling) water, combine mint chocolate chips and butter. Stir until chips are melted and mixture is smooth. Stir in vanilla extract and salt. Transfer to a large bowl. Gradually beat in the confectioners' sugar alternately with milk, beat until smooth. (If necessary add more milk until desired consistency is reached.) Frost layers and garnish as desired.
GARNISHES: Use chocolate curls and grated chocolate on top of the cake. Form a ring of grated chocolate pieces around the outside edge and use the curls in the center. To make chocolate leaves, select several small leaves, wash and dry them and paint one side of them with melted chocolate. Chill until firm, peel the leaf off the chilled chocolate.