place parchment paper to line backing sheet (all 4 sides)(works best to remove bars)
in large bowl combine rhubarb white sugar and 3 tbsp flour stir well
in another bowl combine Brown sugar, oats, and Flour stir well
and cut in butter until crumbly
spread over rhubarb mixture
Bake for 40 min
cool and cut unto bars
Notes
use 9x9 pan greased (or parchment paper(works best getting out).Put 1/2 the crust in the botttom of the pan. pour in the rhubarb on top of the crust. crumble the rest of the crust on top. bake for 35 - 40 min cool and cut unto bars