Place tomatoes on a lightly greased rimmed baking sheet. Roast at 400° for 20 minutes or until tomatoes collapse and begin to brown.
Place potatoes in a lightly greased 13" x 9" baking dish. Sprinkle with roasted tomatoes and chives; toss gently.
Combine 1 egg, mustard, salt, and pepper in a large bowl; whisk until blended. Add remaining 11 eggs, egg substitute, and milk; whisk until blended. Pour over potatoes in dish. Sprinkle with bacon and Parmesan.
Bake, uncovered, at 350° for 45 minutes or until set.