Rinse the lentils and soak them in water for about 30 minutes, or until they double in size.

In a pressure cooker, heat a little olive oil. Add the chopped onion and sauté until soft.

Add the drained lentils. Pour in 4 cups of water for each cup of lentils (measured before soaking).

Add the bouillon cube, salt, and flour. (It's important to add the flour and cold water together to prevent clumping.) Stir well.

Bring the mixture to a boil, then cover the pressure cooker and cook for 10 minutes after it starts to whistle. Let it cool slightly while still covered.

You have two options: either blend the soup in a blender or strain it through a fine sieve (this is my usual method).

Add the olive oil and stir until fully combined. (You can add the oil before pressure cooking, but I prefer adding it at the end to keep its benefits.)

Add a little chopped parsley and lemon juice, then stir. Serve with lemon wedges and toasted bread.