Rhubarb crumb bars

Make this dessert in an 8 by 8 pan in 3 layers.  Spray the pan first then pour in each layer.  Preheat the oven to 350

Layer 1

Mix together then pour in pan:

1 cup white flour

1 cup icing sugar 

1/2 tsp baking powder

1/4 tsp salt

1/2 cup soft margarine or butter

2 eggs

1 tsp vanilla

Layer 2

Mix together then pour in pan:

2 cups chopped rhubarb

1/4 cup flour

1 tbsp brown sugar

Layer 3

Mix with a fork then pour in the pan:

1/4 cup melted butter

1 cup flour

1/2 cup brown sugar

Bake 40-50 min and cut into 16 bars