Pre-heat oven to 400f.
FILLING: In large skillet, brown hamburger and drain. Stir in onion, green pepper, garlic, oregano, salt, water, hot pepper sauce, tomato sauce and sauce mix; simmer about 10 min stirring occasionally.
BATTER: In a bowl, combine milk, oil and eggs; beat 1 min on medium speed. Add flour and salt; beat 2 min or until smooth.
ASSEMBLY: Pour hot meat mixture into 13x9 pan; top with cheese slices. Pour batter over cheese, covering filling completely; sprinkle with parmesan cheese. Bake at 400f for 25-30 min or until puffed and brown.