Mix baking soda into milk and let set until the milk is room temperature

Cut in brown sugar to shortening

Add egg and mix until well blended

Stir in milk and vanilla until well blended

Add flour and salt mix well

Add rhubarb

Grease and flour 9x13 cake pan and pour batter into pan.

Mix sugar and cinnamon and sprinke over the top

Bake at 375 for 30 minutes or until toothpick comes out clean. Let cool completely before cutting