This was adapted from Jamie Oliver with a few additions and adjustments every time we make it. It takes some work, but it is worth it in the end. Changing out your seafood choices as well as your veggie choices and potato choices is always advisable. This makes it new every time you have it.
For this you’ll need: 2 large sweet potatoes, 2 large russet potatoes (or x4 or 5 medium potatoes; both peeled and cut into 1″ cubes), 4 cups heavy cream, 2 shallots (peeled and chopped), 6 garlic cloves (chopped), x4 or 5 fresh thyme sprigs, 3 bay leaves, 1/2 tsp nutmeg, 1/2 red pepper (cored and chopped), 2 cups mushrooms (we used shiitake; chopped), 1 cup frozen peas (rinsed and drained), 1/2 onion (chopped), 2 cups spinach, 1/2 cup white wine, 1/2 lb salmon (cut into 1″ cubes), 1/2 lb haddock (cut into 1″ cubes), 1/2 lb scallops (cut into quarters), 7 Tbs unsalted butter, 1+ cup shredded sharp cheddar cheese, olive oil, salt and pepper.
Preheat the oven to 450.
Melt 2 Tbsp butter in a medium pot over medium heat. Add the chopped shallots and garlic reducing the heat slightly to avoid burning the butter. Stir well to coat and cook until shallots are just softening, about 5 mins. Add in 3 cups of cream, bay leaves, 2-3 sprigs of fresh thyme, nutmeg and a good grinding of salt and pepper. Bring to a boil and reduce the heat immediately so that the cream just simmers. Allow to simmer, uncovered, until thickened and reduced, about 20 mins.
Partially fill a large pot with water and bring to a boil. Add the regular potatoes first and boil for about 6 mins. Then add the sweet potatoes and boil for another 8 mins until a fork easily passes through the boiled cubes. Strain and place the potatoes back into the pot. Mash the potatoes with a masher until well combined and roughly smooth.
In a small pot, melt x4 Tbs butter and then add 1 cup cream and heat through. Add some fresh thyme leaves (2-3 Tbsp) to this butter/cream mixture by pinching the stems with your fingers and scraping the leaves off. Stir in this cream/butter/thyme mixture into the mashed potatoes a little at a time until you have smooth mashed potatoes that are thick enough to stand on their own but smooth enough to spread with the back of a wooden spoon. Add in 1/2 cup shredded cheddar and salt and pepper to taste and stir together well.
In a large skillet melt 1 Tbsp butter in 2 Tbsp of olive oil over medium heat. Add the chopped onion and cook until just soft – about 5 minutes. Add in the chopped red bell pepper and stir together for about 2-3 mins. Add in the mushrooms (and a little more olive oil, if needed) and turn up the heat slightly. Cook until mushrooms are just beginning to brown about 10 mins. Add in the spinach and white wine and turn up the heat again. Cook until the wine has evaporated about 5 mins. Turn off the heat and set aside.
Now, build your pie.
First, strain the infused cream into a serving bowl or measuring cup discarding the solids (shallot, garlic, thyme, bay leaves).
In a high sided casserole pan, place the uncooked seafood evenly across the bottom. Add in the sautéed veggies (bell pepper, mushrooms, onion) and the peas to the uncooked seafood and gently combine together with a wooden spoon. Pour the infused cream across the top of the veggie/seafood mixture and gently stir everything together with a wooden spoon and spread everything evenly across the casserole pan. Sprinkle another 1/2 cup of shredded cheddar across the top.
Add the mashed potato mixture in large dollops equally across the top of the seafood/veggie/cream mixture. With the back of a wooden spoon, gently spread the mashed potatoes evenly across the entire surface. Sprinkle a bit more cheese across the top and place into the preheated oven. Bake until golden and bubbling – about 25 mins.
Remove from oven and let stand for about 10 mins to cool and fuse together.