Apple and hazelnut slaw

Ingredients

• Dressing
• 1 free-range egg yolk
• 1 teaspoon liquid honey, or to taste
• 1 tablespoon sherry vinegar
• 1 tablespoon dijon mustard
• 1/3 cup vegetable oil (such as grapeseed oil, or try a very mild olive oil)
• 2 teaspoons crème fraîche
• Slaw
• 1/3 cup shelled hazelnuts
• 2 crisp apples
• 1 bulb fennel
• juice 1 lemon
• 1/4 red cabbage, thinly sliced
• 1/4 white cabbage, thinly sliced
• 3 stems flat-leaf parsley, roughly chopped
• 1 tablespoon olive oil