The night before cube the potatoes and put them in a large saucepan with salted cold water and place in the refrigerator overnight
Roast the garlic Preheat the oven to 350 degrees F peel the outermost layers of skin off the heads of garlic; cut off the top 1/3 of the heads to open the cloves and heat olive oil in a large oven-safe saute pan over medium heat; Add garlic and saute for about 10 minutes; Season with salt and pepper and transfer pan to the oven to roast for 15 minutes; Remove from heat and let cool
For the garlic paste Pop garlic cloves from their skins and place cloves in a blender along with any olive oil left in the pan; Puree until smooth; you should have a paste-like consistency
For the potatoes The next day add some more salt and then bring to a boil over high heat
Cook until tender about 10 minutes
Drain well place potato cubes in a food mill and grind to remove skins
Alternatively smash the potatoes with a large fork or potato masher
Heat 1 tablespoon of the butter in a large saucepan over medium heat until the butter stops foaming and turns a light brown
Add the garlic paste and cook quickly
Add the cream season to taste with salt and pepper and bring to a boil
Reduce the heat to low and fold in potatoes with a wooded spoon or large whisk
Add the remaining butter by tablespoons until taste suits you stirring after each addition
