Preheat oven to 250 degrees.
In a large bowl, toss tomatoes with balsamic, oregano, and Splenda.
In a nonstick baking pan, bake tomatoes, cut side up, until they are reduced to half their size, about 2 hours.
Remove. Let cool. (This first step can be done up to 3 days ahead of time.)
In a large hot nonstick skillet, saute mushrooms till brown, about 3 minutes.
Add garlic, shallots, and rosemary. Cook for 2 more minutes.
Remove from heat and add spinach. Mix well. Let mushroom mixture cool completely.
When cool, dice tomatoes. In a large bowl, mix tomatoes with mushrooms/spinach mixture, egg whites, breadcrumbs, basil, and parsley.
Preheat oven to 350 degrees. On a large cutting board, pound the chicken breasts to thin them out.
Spread tomato/mushroom/spinach mixture on top of each breast and roll.
Season rolls with paprika. Place rolls in a nonstick baking sheet and bake in 350-degree oven till chicken is cooked, about 15 to 20 minutes.
Let sit for 2 minutes. Slice each roll, if desired, or serve whole.