Place the quartered new potatoes in a medium-size saucepan and cover with water. Add 1 tsp salt. Bring to a boil and cook for 15 minutes or until fork tender.
Drain in a colander and allow to cool for 5 minutes while you make the dressing.
In a large mixing bowl whisk together the mayonnaise, sour cream, buttermilk, dry Ranch salad dressing mix, lemon pepper and black pepper.
Add the potatoes, bacon and green onion. Toss to coat. (Reserve 2 Tbsp each of bacon and green onion for garnishing)
Chill for about 20-30 minutes then add 1 1/4 cup shredded cheese. Mix well.
Serve warm or chilled garnished with reserved bacon, green onion and shredded cheese.