Rhubarb Buckle

For those of us who have a yearly spring love affair with rhubarb- this is a fun recipe to try.  Serve it with vanilla ice cream for dessert, as a coffecake for breakfast, and as an easily toted picnic lunch treat. (Or just eat it out of hand as you pass through the kitchen...)
 
Rhubarb Buckle slightly adapted from Martha Stewart Magazine, May 2012
Ingredients:
Cake:
1 lb. plus 10 oz. fresh rhubarb pieces (about 2 lbs stalks untrimmed)
2 cups sugar, divided
2 cups all-purpose flour
1 1/4 tsp. baking powder
1 tsp. coarse salt
1 1/2 sticks (3/4 cup) unsalted butter, softened
1 tsp. finely grated lemon zest
3 large eggs
1 tsp. pure vanilla extract
1/2 cup sour cream

Crumb topping:
1 cup all-purpose flour
1/4 cup light brown sugar
1/4 tsp coarse salt
1/2 stick (1/4 cup) unsalted butter, melted

Directions:
1. Cake: Preheat oven to 350°, with rack in center position. Coat one half sheet pan or two 9in. square cake pans with cooking spray, and line with parchment, leaving an overhang on 2 sides. Stir together rhubarb with one cup sugar, set aside. (Note: I used the half sheet pan; it decreases the amount of cake in each cut square, which I like.)
2. Whisk together flour, baking powder, and salt. Beat together butter, remaining cup sugar, and the lemon zest until light and fluffy. Beat in eggs one at a time, then beat in vanilla. Beat in flour mixture in two additions, alternating with sour cream, beginning and ending with flour mixture.
3. Crumb topping: Stir together flour, brown sugar, and salt. Add melted butter and stir to combine until crumbly.
4. Pour cake batter into pan(s). Spoon rhubarb mixture evenly over cake batter, and sprinkle with crumb topping.
5.Bake until golden on top and cooked through, about 1 hour. Let cool completely in pan. Lift cakes from pan(s) using parchment. Cut into 2 in. squares.

Cake(s) can be wrapped in plastic and stored at room temperature for one day. If storing, remove parchment before wrapping in plastic.