Pre-heat your oven to 190C / 375F / gas mark 5.
Cut the tops off of the garlic heads and remove any loose papery skins.
Put the garlic heads into an oven dish and drizzle with the olive oil and season with salt and pepper.
Cover with foil and place in the centre of the oven making sure that the foil isn't touching the tops of the garlic.
Roast the garlic for 1 hour 15 minutes or until the garlic is soft.
Leave the garlic to cool before squeezing the soft, caramelised garlic cloves into a bowl.
Next, melt the non-dairy butter on a medium heat in a large, heavy bottomed saucepan.
Mash the garlic until it forms a paste then add to the melted butter.
Cook the butter and garlic for 5 minutes until they have combined.
Add in the flour and stir well to form a roux.
Pour in the vegetable stock slowly, stirring as you go.
To get a super smooth soup, transfer to a blender and blitz on high for 2-3 minutes or until there are no lumps. Return the soup to the pan and add in the dried mixed herbs. (Alternatively use a stick blender and blitz in the saucepan).
Bring the soup to a simmer and cook for 15 minutes.
Turn the heat to low and stir in the cream.
Season to taste then let simmer for a further 10 minutes.
In the meantime, finely chop the parsley.
Add the parsley to a small bowl along with the lemon juice and roughly the same volume of olive oil.
Whisk the parsley, olive oil and lemon juice mix.
Serve the soup and drizzle over the parsley oil.
Finally top with croutons if desired.