1Preheat oven to 350 degrees. In a small skillet melt butter over med heat. Add onion: cook until onion is tender but not browned. Remove from heat.
To this add tomatoes and the package of Hidden Valley Ranch mix; mix well.
2In a large bowl, stir ricotta cheese and egg until well blended. Add brocolli and Jack cheese. Mix well.
3In a large kettle of boiling water, cook pasta shells for 9 minutes or until tender but firm to the bite; drain. Rinse with cold water; drain again.
4Stuff each shell with about 2 Tablespoons of broccoli-cheese mixture.
5Pour one-third of tomato mixture into a 9x13 baking dish. Arrange filled shells on top. Spoon remaining tomato mixture over top. Sprinkle Parm cheese on top. Bake,covered, for 30 minutes or until hot and bubbly. Serve with a side salad and garlic bread!