White Pizza Dip

1 cup sour cream
1 cup ricotta cheese
1 cup shredded mozzarella cheese
1/2 cup chopped pepperoni
1 package Lipton's herb with garlic soup mix
1/8 teaspoon red pepper flakes (optional)

Mix all ingredients well. Place in a casserole dish and bake at 350 degrees F for 25 - 30 minutes.