Place all of the 'Chermoula' ingredients in a medium mixing bowl and whisk until thoroughly combined and smooth - Transfer half to a small bowl and set aside until needed
Add the fish fillets to the mixing bowl and thoroughly coat with the chermoula - Set aside until needed
In the dish of the tagine*, add about 2 Tbs of the reserved chermoula to coat the bottom - Place the onions in a single layer - Arrange the carrots over the top of the onion - Arrange the potatoes in a single layer and sprinkle with the salt, pepper, and turmeric - Arrange the tomatoes over the potatoes
Mix the remaining reserved chermoula with ½ cup water and pour over the vegetables
Place the fish fillets on top of the vegetables and drizzle any remaining marinade over the top - Arrange the bell pepper rings and half of the lemon slices over the fish
Cover and place in a COLD oven* - Set oven temperature to 350ºF and allow to cook until fish is cooked through / flakes easily and potatoes are fork tender (apx 45 minutes - 1 hour)
Remove from oven - If the sauce is really 'watery' , you may wish to carefully ladle it into a sauce pan and reduce separately until thick and 'coating' before pouring back into the tagine
Garnish with a bit of chopped parsley or cilantro and the remaining lemon slices - Serve hot with Khobz (Moroccan bread) and/or couscous
*You can use a Dutch oven instead of a tagine for this however, cook times will vary slightly - If using a
Dutch oven (or cast iron tagine - yes, they make those!), you do not have to place in a cold oven, you
can preheat - The reason for the cold oven and slow increase of heat is to avoid thermal shock that
could crack a more traditional earthenware or ceramic tagine