Outback Steakhouse Ranch Dressing

1 packet Hidden Valley Ranch Dressing Mix, Buttermilk Recipe (0.4 oz package or approx. 1 heaping tablespoon)
1/2 cup light mayonnaise
1/2 cup light sour cream
1/2 cup buttermilk
1/4 tsp. freshly ground black pepper
1/4 tsp. ground cayenne pepper (or 1/8 tsp. for less heat, or use 1/4 tsp. paprika)
1/8 tsp. garlic powder
1/8 tsp. onion powder

Whisk together all ingredients in a medium sized bowl. Cover and chill for at least 1 to 2 hours, preferably overnight. Use as dressing for salads or a dip for veggies, fries or chips.

Note
If you are out of buttermilk like I was, add 1/2 tbsp. vinegar into a 1/2 cup measuring cup. Fill the measuring cup the rest of the way full with skim milk and allow to sit for 10 minutes before adding to mixture.