Combine the first 3 ingredients in a bowl; stir well. Gradually add water and next 2 ingredients, stirring with a wire whisk until blended; set aside.
Gradually add water and next 2 ingredients, stirring with a wire whisk until blended; set aside.
Cook the onion and beef in a large saucepan coated with cooking spray over medium-high heat until browned, stirring to crumble; drain in a colander.
Return beef mixture to pan.
Add parsley and next 5 ingredients; stir well.
Add broth mixture; cook over medium heat for 15 minutes or until thickened, stirring constantly.
Spoon mixture into a 13 x 9-inch baking dish coated with cooking spray.
Carefully split biscuits in half horizontally, and place over beef mixture.
Bake at 400 degrees for 10 minutes or until biscuits are lightly browned.
Make-Ahead Tips: You can assemble the casserole ahead of time, without thawing the frozen vegetables and omitting the biscuits; cover and freeze. Thaw frozen casserole overnight in refrigerator; let stand at room temperature 30 minutes. Top with biscuits; bake as directed.