Rhubarb dessert cake

very light on the instructions.
Jean

Ingredients

1 1/2 cup brown sugar
1/2 cup shortening
1 egg
1 cup sour milk (buttermilk?)
1 tsp baking soda
2 cups flour
1 tsp vanilla
1 1/2 cups chopped rhubarb

Topping
1/3 cup sugar
1 tsp cinnamon

Instructions

45 minutes.