3 large starchy potatoes, peeled and cubed
1 1/4 pounds fresh cod
1/4 cup vegetable oil
2 teaspoons seafood seasoning blend (2/3 palmful), such as Old Bay brand
2 ribs celery and their greens, finely chopped
1 small yellow onion, peeled and finely chopped
2-3 tablespoons fresh thyme leaves (a few sprigs), chopped
3-4 tablespoons fresh flat leaf parsley (a handful), chopped
2 cups plain breadcrumbs
4 tablespoons butter
1/2 red bell pepper, finely chopped
1 shallot, finely chopped
2 tablespoons all-purpose flour
2 cups chicken stock
1 clove garlic, finely chopped
1/4 cup cream or half-and-half
1 pound triple-washed spinach, stemmed and chopped
Place potatoes in a pot and cover with cold water. Put a lid on the pot and bring the water up to a boil. Salt water and cook potatoes until tender, 15 minutes.
Bring 1/2-inch water to a simmer in a large nonstick skillet. Zest a lemon and reserve. Cut lemon and season the fish with some lemon juice and salt and add to the simmering water. Cover pan and cook fish for eight minutes.
Remove and flake fish into a bowl. Discard water and wipe out pan, returning it to medium heat. Add 1/4 cup vegetable oil to the pan. Add reserved lemon zest, seafood seasoning, celery, onion, thyme, parsley, salt and pepper to fish. Add egg and one cup of the breadcrumbs. Form eight fish patties and toss in remaining breadcrumbs to set the patties.
Cook the patties in the oil for 4-5 minutes on each side until golden. Reserve under foil or in warm oven. Return skillet to heat again over medium heat. Melt in two tablespoons of butter, then add the red bell peppers and shallots and cook for 2-3 minutes. Add in flour and cook a minute more. Whisk in broth, thicken, then season with salt and pepper to make savory red pepper gravy.
Drain cooked potatoes and return to hot pot. Add in remaining butter, garlic and 1/4 cup cream or half-and-half. Mash and season the potatoes with salt and pepper. Fold in spinach leaves until they all wilt into potatoes.
To serve, pile spinach mashers on plates and top with cod croquettes and gravy.