Heat a barbecue grill plate to hot or a large chargrill pan over high heat.
Brush the steaks with the coconut oil or fat and season with salt and pepper. Cook the steaks on one side for 3 minutes, or until golden, then flip and cook the other side for 3 minutes for medium-rare. Place the steaks on a plate, loosely cover with a cloth and rest for 4-6 minutes, keeping warm.
Place all the dressing ingredients in a bowl and whisk to combine. Season with salt and pepper to taste.
Place all the herb salad ingredients in a large bowl, pour in only enough dressing to coat the leaves and gently toss.
To make the mustard aioli, mix the mayonnaise, mustard and garlic confit together and season with salt and pepper if needed.
Spoon the remaining dressing over the steak, if desired, and serve with the salad and mustard aioli.