In a mixing bowl, put flour, baking soda, and salt. Add sugar and mix. Stir in oatmeal and nuts and then butter. Make a crumbly mixture. Put this into an unbuttered 8-inch square pan. Press the dough to make a smooth layer. Bake for 10 minutes while preparing the topping.
Sift topping flour, baking soda, and salt. Melt chocolate and butter in the microwave; stir until smooth. Mix the sugar and egg. Stir in the vanilla and milk. Add the dry ingredients, and stir until smooth. Pour the chocolate topping over the hot bottom layer, and spread smoothly. Bake for 35 minutes. Do not overbake; the chocolate should still be moist. Cool completely in the pan. Yield: 16 bars.