4 large baking potatoes, peeled and thickly sliced
3 tablespoons extra virgin olive oil (EVOO)
2 onions, thinly sliced
3-4 ribs celery from the heart, with leafy greens, chopped
3-4 cloves garlic, finely chopped
1 large bay leaf
2 tablespoons fresh thyme leaves, chopped
Grated peel and juice of 1 lemon
1/2 cup dry white wine
1 cup chicken stock, divided
1 can diced or stewed tomatoes (14.5-ounces)
1 1/2 pounds thick cod fillets, cut into chunks
1 pound large shrimp, peeled and deveined
1/4 cup white balsamic vinegar or white wine vinegar
2 tablespoons butter
In a deep pot, add the potatoes and enough water to cover. Bring to a boil, salt the water and cook the potatoes until tender, about 15 minutes. Drain.
In a Dutch oven or a large, deep skillet with a lid, heat the EVOO, three turns of the pan, over medium-high heat. Add the onions, celery, garlic, bay leaf, thyme and lemon peel; season with salt and pepper. Cook until the onions are softened, 7-8 minutes. Pour in the wine and cook for 1 minute. Stir in 1/2 cup chicken stock and the tomatoes with their juice; bring to a simmer. Add the cod in a single layer, then cover and cook for 3 minutes. Gently stir in the shrimp; season with salt and pepper. Cover and cook until the cod and shrimp are just opaque throughout, about 3 minutes. Remove from the heat and stir in the lemon juice; discard the bay leaf.
Mash the potatoes with the remaining 1/2 cup chicken stock and the vinegar and butter; season with salt.
To serve, mound the potatoes into shallow bowls. Ladle the stoup around the potatoes.