Parsley mayonnaise

Put the parsley and oil in a food processor or blender and blitz until the oil turns green

Transfer the oil to a saucepan. Bring to a simmer (this will help ‘set’ the colour of the oil), then strain through a fine sieve lined with muslin or kitchen paper into a bowl. It may take a while to strain through, but don’t be tempted to help it along or speed things up as it’ll make the oil cloudy

Whisk together the egg yolk, mustard and lemon juice. Once the oil has finished straining and has cooled, very slowly drizzle it into the yolk mixture whilst whisking constantly. If the bowl is moving around too much while you do this, sit it on a few damp tea towels to hold it in place

Once the mayonnaise begins to thicken and emulsify, you can start adding the oil a little quicker. Season to taste with plenty of salt and pepper, then garnish with some extra parsley leaves