Wash the potatoes and rosemary and pat dry.
Add the olive oil and crush garlic to a mixing bowl.
Add chopped rosemary and some salt and pepper.
Add in the quartered red potatoes and toss the potatoes with the oil and rosemary.
Place a few spoonfuls on a piece of foil.
Wrap the potatoes into packets.
Grill the potato packets for about 10-15 minutes, or until they look like this.
Transfer the potatoes to the mixing bowl and mash gently. Stir in the sour cream, and any other mix-ins.
Serve Grilled Red Potato Salad warm or cold.