Turn the oven to 200°C (400°F) fan bake.
Cover the potatoes with water in a medium pot over high heat and boil for 10 minutes until the potatoes are al-dente. Drain and run under cold water until the potatoes are cold enough to handle. Slice the potatoes into ½ cm slices and layer them in a 30 x 20 cm rectangle baking dish or something similar.
Meanwhile, make the cheese sauce while the potatoes are boiling. Blend all the ingredients for the cheese sauce in a high-speed blender until smooth. Pour the sauce over the potatoes and bake on the top shelf for 20-25 minutes until bubbling and browned, then turn the oven to grill and grill for 2-3 minutes.
In a bowl, mix the red onion, black beans, balsamic vinegar, maple syrup, parsley and cajun seasoning.
Serve the creamy scalloped potatoes with a side of rocket, black bean salad and avocado. Sprinkle the bean salad with chilli flakes (optional). Enjoy.