Coarsely chop the onion.
In a pot heat 2 tbsp olive oil and sauté the onion on a low/medium heat for about 3-4 minutes stirring frequently. Add the flour and cook for about a minute until thick.
Add the stock and on a high heat bring it to a boil. Turn down the heat, add the garlic and continue simmering for 20 mins.
While the soup is simmering, make the croutons.
With a knife or scissors, cut a half pita bread into 1” strips.
Separate the two layers of pita bread and cut each strip into 1/2” wide pieces.
In small saucepan, add 1 tbsp olive oil and the pita squares and on a low fire, start frying the croutons. When they start to sizzle, stir frequently with a soup spoon to avoid burning.
Once crispy (about 2-3 minutes), drain through kitchen towel in a small bowl or plate. Set aside.
Blend the garlic and onion mixture with a hand blender. Set aside till ready to serve.
When ready to serve, bring the garlic onion mix to a gentle simmer and stir in half a cup of double cream.
Serve each portion through a fine sieve. With a wooden spoon squeeze out any onions or garlic that remain.
Garnish with croutons and cracked pepper.