Make a parcel with tin foil and place the garlic cloves in it, spray them with a little oil spray and roast in the oven for 15 minutes. Remove from oven and allow to cool a little so parcel can be handled.
Spray the bottom of a large saucepan 5 times, turn the heat on high and when the oil starts to bubble turn the heat to a medium heat and add the diced onion. Sauté for approximately 5 minutes.
Once the garlic parcel is cool enough to handle remove the roasted garlic cloves from it and squeeze the soft cloves out of their skins adding to the sautéed diced onion.
Add the chopped potatoes and vegetable stock to the saucepan.
Cook for about 15 – 20 minutes until potatoes are soft and then turn off the heat and allow to cool a little.
Blitz the mixture in a food processor, return to the pan and season to taste.