One-Pan Tuna-White Bean Casserole

This is not the classic, cream-of-something soup tuna casserole you may be familiar with. It’s based on a recipe for a Breton tuna and white bean gratin from the food writer Diana Henry’s cookbook, “Simple” (Mitchell Beazley, 2016). Several steps were eliminated, and an essential potato chip topping was added, which may put it squarely into tuna casserole territory. But you can call it whatever you like. (This recipe is part of the From the Pantry series, started in the days after the coronavirus lockdown.)

Ingredients

• 1

  onion, 2 shallots, 4 scallions or 2 leeks, chopped

• 2

  tablespoons olive oil

• Pinch of red-pepper flakes

• Pinch of kosher salt

• 6

  garlic cloves, sliced

• 1

  rosemary sprig (optional)

• 2

  anchovy fillets (optional)

• 2

  (15-ounce) cans white beans, drained and rinsed

• ½

  cup white wine, or use water or broth

• ¼

  cup milk

• 2

  (5-ounce) cans of tuna

• 1 to 2

  tablespoons chopped fresh herbs such as parsley, basil, tarragon, chives or a combination

• Zest of 1/2 lemon

• Kosher salt and black pepper

• 4 to 6

  tablespoons grated cheese (any kind, though Gruyère, Cheddar, Parmesan or Jarlsberg would be great)

• ½

  cup potato chips, crushed

• 1

  tablespoon butter, cut into small pieces

• Lemon juice, for serving

Preparation

1. Heat oven to 350 degrees. In an ovenproof skillet, sauté a chopped onion (or shallots, scallions or leeks) in olive oil over medium-high heat until soft, about 5 minutes.
2. Add red-pepper flakes, salt and garlic cloves. Throw in the rosemary sprig, if using. Add anchovy fillets, if using. Cook for another 2 minutes, until the garlic is slightly golden and very fragrant.
3. Add the white beans and the wine. Let it simmer until the liquid evaporates and the beans are soft, about 5 minutes, then mash the beans with a potato masher or a fork. Make them as smooth or lumpy as you like. You just want to release some of their starch. Turn off the heat.
4. Now, add the milk and the tuna. If you have the oil-packed kind, add the oil. If you have the water-packed kind, drain them, and drizzle in more olive oil.
5. Mash the tuna into the beans, leaving it a little chunky. Mix in the herbs, lemon zest and add lots of black pepper. Finally, mix in 2 to 4 tablespoons of any kind of grated cheese. Taste and add more salt and pepper if needed.
6. Spread the mixture evenly in the skillet, and top it with potato chips. Scatter on more grated cheese, about another 2 tablespoons, and dot the top with little nuggets of butter.
7. Bake until the tuna mixture bubbles around the edges, 20 to 25 minutes. If you want the potato chips to get more brown, you could run the whole pan under the broiler. Finish with lemon juice.