Armenian Nutmeg Cake

My mum made this cake in the 80's. It's got a bit of magic about it in that you make a crumble-like mixture with the sugar, flour and butter then press half of it in the bottom of a tin to make a delicious shortbread base then with the other half you add freshly grated nutmeg milk, eggs and nuts and pour over the base. It is a winner all around ... and to my knowledge contains no Armenians nor has any link with Armenia!
     2 cups lightly packed brown sugar (I use light)
     2 cups self raising flour
     125 gm. butter
     l tsp. bicarbonate soda
     l cup milk
     l large egg, lightly beaten
     l or 2 teaspoon nutmeg (I always use freshly grated. So good)
     1/2 - 1 cup walnuts (optional) (and I've used 1 cup of pecans in my recipe)
Place brown sugar and flour into mixing bowl - add butter and rub in.
Grease a deep round or square cake tin and spread half of crumb mixture over the base.
Press down - not too hard as it makes it difficult to cut through.
Mix bicarbonate soda into milk, egg and nutmeg and add to remaining crumb mixture and stir to a thick batter. Pour over base.
Sprinkle with chopped nuts of your desire or leave plain.
Bake in moderate oven (180c) for approx. one hour. Cool a little before turning out.