Bring the water to a boil in a large saucepan; gradually stir in grits. Reduce heat, and simmer 30 minutes or until thick, stirring frequently.
Remove from heat. Stir in 1/4 cup cheese and 1/2 teaspoon salt. Spoon grits mixture into an 11 x 7-inch baking dish coated with cooking spray.
Preheat oven to 35
Melt butter in a large nonstick skillet over medium-high heat.
Add onion and garlic; saut 3 minutes or until tender.
Add remaining 1/2 teaspoon salt, mushrooms, herbes de Provence, and pepper; cook 6 minutes or until mushrooms are tender, stirring frequently. Stir in prosciutto and wine; cook 5 minutes or until liquid almost evaporates.
Remove from heat; cool slightly. Stir in eggs and egg whites.
Spread mushroom mixture over grits mixture; sprinkle with remaining 1/2 cup cheese.
Bake at 350 for 30 minutes or until cheese melts and grits are thoroughly heated, and let stand 5 minutes before serving.