One of my favorite desserts of all of them. And it doesn't even have any chocolate in it.
My stand mixer really helped to mix the topping for this. The mixture gets quite thick.
1 cup brown sugar
1 1/2 sticks (3/4 cup) butter
1/2 cup old fashioned oats
1/2 cup flour plus 1 1/2 T
1 cup walnut pieces
4 1/2 cups chopped rhubarb
Preheat oven to 350°. Spray an 8" square pan with cooking spray. Set aside.
In the bowl of a stand mixer, cream brown sugar and butter. Mix in oats and 1/2 cup flour. Slowly add in nuts til mixture resembles coarse crumbs. Set aside.
Add rhubarb to prepared pan. Stir in 1 1/2 T flour.
Dollop oat topping over rhubarb.
Bake about 40 minutes or til topping is golden brown and rhubarb is bubbling. Let rest 10 minutes or so before serving. If you can wait that long.