This really does taste like the Cafe Rio House dressing!
1 pkg Hidden Valley ranch dressing mix
1 C mayonnaise
1 C chopped cilantro
2 cloves garlic
3 tomatillos (canned -found on ethnic foods aisle)
1/3 C buttermilk
1/4 t cayenne pepper
Put all ingredients in blender and blend until smooth.
Refrigerate until you are ready to use.