Preheat oven to 350 degrees. Lightly coat a 2 quart baking dish with nonstick cooking spray or oil. Place potatoes and garlic in a large saucepan and cover with cold water. Bring to a simmer over medium heat. Reduce the heat to low and cook until the potatoes are barely tender, 15 to 20 minutes.
Drain and let sit until cool enough to handle, about 20 minutes. Peel the potatoes and grate them into a large bowl; set aside. Squeeze the garlic cloves from their skins into a food processor. Add cottage cheese and process until completely smooth. Add sour cream, salt and pepper and process briefly to combine. Add the cottage cheese mixture and scallions to the grated potatoes and mix well. Turn into the prepared baking dish and sprinkle with grated Cheddar and paprika. (The recipe can be prepared ahead to this point and stored, covered, in the refrigerator for up to 2 days.) Bake for 30 to 40 minutes, or until golden brown.