Peel several potatoes and slice lengthwise about 1/4 inch thick. Place in a bowl of water for 20-30 minutes.
Slice several yellow onions into rings also 1/4 inch thick. Place in separate bowl. Toss a handful of cherry tomatoes in olive oil and Provençal spices and set aside.
In a large ovenproof dish scatter the onions and drizzle with olive oil and salt and pepper. Place in pre-heated 350 degree oven for 10-15 minutes or until they begin to soften.
Drain and dry potatoes and place on top of the onions and bake for another 15 minutes or until they begin to soften. Drizzle olive oil and lightly season before placing in the oven.
Then add a third layer of tomatoes. Drizzle with oil and season. Bake for 10-15 minutes. Add seasoned fish--halibut, cod, or other mild white fish.
Option: top fish fillets with anchovies, toss in some olives, capers and sprinkle with Provençal herbs.
Bake until fish is tender.
Tip: lightly season as you go and scale the salt based on your use of anchovies, capers and olives. Everything but the fish could be prepared ahead and kept warm until needed.
Serve with good bread to soak up pan juices. Side of sautéed escarole with garlic and shallots.