To make this garlicky mayonnaise-type sauce, grind 1 small garlic clove with ½ tsp sea salt to a paste in a pestle and mortar. In a large bowl, whisk together 1 large egg yolk with 1 tsp Dijon mustard or English mustard powder until smooth and creamy. Gradually whisk in 150 ml/5 fl oz/scant ⅔ cup light olive oil until you achieve a mayonnaise consistency. Stir in the juice of ½ lemon and taste, adding more salt if needed. For an extra lemony aioli, stir in 2 tsp finely grated lemon zest.