Rinse then soak the cashews in a bowl of hot water for 25 minutes. Drain and rinse again then transfer them to a powerful blender together with the garlic, the flesh of the avocado, lemon juice, dijon and the water (or aquafaba). Process until smooth and creamy. If the texture is grainy you’ll need to blend again but Do Not add more water. Season to taste with a pinch of sea salt and refrigerate until needed.