Method
Step 1
Preparation: Prepare all ingredients as indicated above.
Step 2
Mustard mayo sauce: Mix together the mayonnaise, wholegrain mustard, apple cider vinegar and dill, season with salt and pepper to taste and whisk in water (2 tsp for 4; 1 tsp for 2; ½ tsp for 1) to loosen.
Step 3
Veggies: Place a pan on medium-high heat with a drizzle of olive oil. Add the onion and celery with a pinch of salt and cook for 5 minutes until softened. Add the garlic and sauté for 30 seconds, then add the cauliflower and cook for another 5 minutes until golden. Add the Swiss chard and red spinach and wilt for 1 minute. Season with salt and pepper, remove from the pan and set aside.
Step 4
Mackerel: Using the same pan on medium-high heat, add the mackerel and warm for 1 minute each side.
Step 5
Serve the mackerel (be careful of the bones when eating) covered in the mustard mayo sauce and serve the veggies on the side.