Step 1

Preheat oven to 375°. In a large bowl, combine flour and baking powder. Cut in butter until mixture resembles coarse crumbs. Stir in eggs and milk just until moistened. Press onto the bottom of a 15x10x1-in. baking pan coated with cooking spray. Top with rhubarb; sprinkle with gelatin.

Step 2

For topping, in a small bowl, combine sugar and flour. Cut in butter until mixture resembles coarse crumbs. Sprinkle over top. Bake until lightly browned, 35-40 minutes. Cool on a wire rack. Cut into bars.