Sprinkle salt over garlic and mash together to make a paste, the finer the better. Combine the paste with all ingredients except lettuce. Taste and adjust the seasoning, if needed. Chill for several hours before serving. When ready to serve, thin with more buttermilk if needed.
Wash and dry the lettuce. Cut into wedges.
To serve: place wedges on a platter or salad plates and drizzle dressing over wedges, making sure you have enough for all the lettuce leaves.