Avocado and sweet potato salad

A tasty sweet potato and avocado salad which makes good use of seasonal produce.   Ingredients (serves 6): 1 egg yolk 2½ tsp finely chopped fresh ginger 2 tbs white vinegar 1 tbs Dijon mustard 1 tbs brown sugar 250ml (1 cup) avocado oil 700g sweet potatoes, peeled, cut into 5mm-thick slices 60ml (¼ cup) olive…