Rhubarb Squares

I love love love rhubarb!

1 box Betty Crocker® SuperMoist® yellow cake mix
1 cup cold butter or margarine, cut into small pieces
1 3/4 cups sugar
3 eggs
4 cups sliced fresh rhubarb
Whipped cream, if desired


1.
Heat oven to 350°F (325°F for dark or nonstick pan). Reserve 2 tablespoons of the cake mix. In large bowl, cut butter into remaining cake mix, using pastry blender (or pulling 2 table knives through ingredients in opposite directions), until crumbly. In bottom of ungreased 13x9-inch pan, pat 2 1/4 cups of the mixture (if mixture is sticky, lightly flour hands). Reserve remaining crumbly mixture for topping. Bake 15 minutes. Remove from oven.
2.
In large bowl, beat reserved 2 tablespoons cake mix, the sugar and eggs with electric mixer on medium speed until creamy. Stir in rhubarb. Pour over partially baked crust. Sprinkle remaining crumbly mixture over top.
3.
Bake 45 to 55 minutes longer or until golden brown and center is set. Cool slightly before serving. Serve warm or cold with whipped cream. Store covered in refrigerator.