Preheat oven to 350.

In a bowl, combine the cream cheese, 1/3 cup sugar, egg, and 1/8 teaspoon salt. Beat well. Stir in the chocolate chips.

In another bowl, mix together the flour, sugar, cocoa, baking soda and 1/2 teaspoon salt. Add the water, cooking oil, vinegar and vanilla. Stir until well blended.

Grease two muffin tins: one tin that holds a dozen, and another that holds a half-dozen. You'll probably only need three or four in the half-dozen pan.

Pour the chocolate batter into the muffin cups until each is about one-third full. Drop a generous dollop of the cream-cheese-chocolate-chip mixture into the center of each one.

Sprinkle a little sugar over each one, and finely chopped nuts, if you like.

Bake 28-30 minutes. Check for doneness with a toothpick; it should come out clean. Don't over bake.

Cool completely before removing cupcakes from tins.