2 Pound(s) baking potatoes (about 4) peeled and cut in chunks
1 1/4 Teaspoon(s) salt
1/2 Teaspoon(s) fresh-ground black pepper
4 Tablespoon(s) butter, at room temperature
1/2 Cup(s) heavy cream, light cream, or milk
2 Pound(s) cod fillets, cut to make 4 pieces
2 Teaspoon(s) cooking oil
4 Each(s) cloves garlic, minced
Heat the oven to 450. Put the potatoes in a medium saucepan of salted water. Bring to a boil and continue boiling until tender, about 15 minutes.
Drain the potatoes and put them back into the saucepan along with 3/4 t. salt and 1/4 t. of the pepper. Mash the potatoes over very low heat, gradually incorporating the butter and cream.
Rub the cod with the oil and sprinkle with the remaining 1/2 t. salt and 1/4 t. pepper. Put the cod in a large roasting pan, sprinkle the fillets with garlic, and then spread with the mashed potatoes. Roast until the fish is nearly done, 8 to 10 minutes for 3/4-inch thick fillets.
Heat the broiler. Broil the fish until the mashed potatoes have a golden brown crust, about 2 minutes.