Sour Cream Rhubarb Coffee Cake

1 1/2 cups brown sugar, packed
1/2 cup shortening
1 egg
1 tsp vanilla extract
2 cups all-purpose flour
1 tsp baking soda
1/2 tsp salt
1 cup sour cream
1 1/2 cups rhubarb, chopped

1/2 cup granulated sugar
1/2 cup walnuts, chopped
1 tsp ground cinnamon
1 tbsp butter, melted and cooled

Preheat oven to 350 degrees

Grease and flour a 13 x 9 baking pan. In a bowl, beat brown sugar and shortening until fluffy; beat in egg and vanilla. In another bowl, mix flour, soda and salt. Add flour mixture to first bowl, alternately with sour cream. Sir in rhubarb. Pour mixture into prepared pan.

Mix granulated sugar, walnuts, cinnamon and butter in a bowl until crumbly; sprinkle over mixture in pan. Bake 45-50 minutes. Cut into squares.