Grease 1-1/2-quart souffle or casserole dish; sprinkle with 2 Tbsp. of the cereal. Set aside.
Bring milk to boil in medium saucepan on medium heat. Gradually stir in remaining 1/2 cup cereal; cook 2 to 3 minutes or until thickened, stirring constantly. Remove from heat; cool 5 minutes. Add cheese, onion, parsley, ham and 1 of the egg yolks; mix well. (Reserve remaining 2 egg yolks for another use.) Set aside.
Beat egg whites with electric mixer on high speed until stiff peaks form. Add to cereal mixture; stir gently with wire whisk until well blended. Pour into prepared dish.
Bake at 400°F for 35 to 40 minutes or until center is set and top is golden brown. Serve immediately.