Proceed to strain them, move carefully with a knife and remove the skin, but not completely. Return to the potatoes to the pot without water. Use a masher or a fork to mash the potatoes. Add the butter, keep mashing with a fork to prevent lumps. Add the milk little by little with the roasted garlic. After mashing and mixing the ingredients, check the texture. If it needs to be softer, add a bit more milk and butter. Add the blue cheese in a folding motion. Season with salt to your liking. Serve hot.