In a 4 - 5 quart dutch oven place potatoes, garlic if using and salt, cover with cold water.
Bring to a boil, lower heat, cover and simmer for 25 minutes, or until fork tender.
When potatoes are just about finished cooking. Place cream and butter in a saucepan, and heat just until butter is melted.
Drain your potatoes and place in a large mixing bowl.
Mix the potatoes for a few second to break up. Then add the cream mixture. Continue mixing on low speed till smooth.
Now, fold in the sour cream, salt and pepper.
Quick note: Sometimes to change things up; I use 1 1/2 pounds russets, or Yukon golds and 1 1/2 pounds red potatoes.