Melt Bakers chocolate with butter in bowl in microwave or on stovetop on low heat. For microwave, heat 30 seconds at a time, stirring after each heating. Cool slightly.
Take melted chocolate and add sugar and eggs beating with mixer after each egg added. Mix in salt, baking soda and vanilla. Then add flour a 1/2 cup at a time, alternating with buttermilk with electric mixer for 1 minute for each flour and buttermilk addition.
Pour into greased baking pans. You can use a 9 x 13" pan or 8-9" rounds &/or cupcakes.
Bake at 350º 25-40 minutes depending on size of pans- slightly less time for cupcakes. Make sure cake has completely risen and bounces back when lightly touched in the center, or a toothpick comes out clean. Cool 20-30 minutes or more before removing from pans to add icing.
Melt together chocolate and butter in microwave or on stovetop on low or 30 sec at a time in microwave.
Add powdered sugar, vanilla, and milk and beat with mixer till fully blended and fluffy. Because you are using melted butter and chocolate, the mixture should be slightly runny. Refrigerate 1 hour before frosting, stirring a few times. If the icing is now too stiff you may add a little more milk then refrigerate a few more minutes.
Frost cake as desired. You don't have to refrigerate this cake after frosting.