Ingredients:

  • 4 large banana shallots (approx. 250 g), thinly sliced into rings
  • 50 g (1/2 cup) all-purpose flour, seasoned with salt and pepper
  • 500 ml (2 cups) vegetable or neutral oil, for frying
  • Pinch of sea salt, for finishing
  • 1 kg (2.2 lbs) fresh green beans (Haricots Verts preferred), trimmed
  • 1 tbsp coarse salt (for blanching water)
  • 60 g (4 tbsp) unsalted butter
  • 250 g (8 oz) Cremini or chestnut mushrooms, finely sliced
  • 2 cloves garlic, minced
  • 2 tbsp fresh thyme leaves
  • 60 g (1/2 cup) all-purpose flour
  • 480 ml (2 cups) whole milk or half-and-half (single cream), warmed slightly
  • 240 ml (1 cup) low-sodium chicken or vegetable stock
  • 1 tsp Worcestershire sauce (optional)
  • 1/2 tsp freshly grated nutmeg
  • Salt and black pepper to taste

Instructions:

  1. Blanch the Beans: Bring a large pot of salted water to a rolling boil. Drop the trimmed green beans in and cook for 3-4 minutes (until bright green and tender-crisp). Immediately plunge them into an ice bath to stop the cooking and set the color. Drain thoroughly and set aside.
  2. Prepare Shallots: Slice the shallots thinly. Toss them thoroughly with the seasoned flour, ensuring they are well coated.
  3. Heat Oil: Heat the oil in a heavy-bottomed pan to 175°C (350°F). Use a thermometer for accuracy.
  4. Fry in Batches: Fry the shallots in small batches, stirring occasionally, until deeply golden brown and crispy (approx. 4–6 minutes per batch).
  5. Drain and Season: Remove the crispy shallots using a spider strainer and place them on a rack or paper towel-lined plate. Immediately sprinkle with a pinch of salt. Set aside. Reserve 3/4 for the topping and 1/4 to mix into the casserole base.
  6. Sauté Aromatics: Melt the butter in a large saucepan over medium heat. Add the sliced mushrooms and sauté until they have released their liquid and browned (7–10 minutes). Add the minced garlic and thyme; cook for 1 minute until fragrant.
  7. Make the Roux: Sprinkle the 60g flour over the mushroom mixture. Stir constantly for 2 minutes to cook out the raw flour taste.
  8. Whisk in Liquids: Slowly whisk in the warmed milk, followed by the stock, ensuring no lumps form. Bring the mixture to a gentle simmer, whisking occasionally.
  9. Thicken and Season: Reduce the heat and let the sauce simmer until it thickens to coat the back of a spoon (about 5 minutes). Stir in the Worcestershire sauce and nutmeg. Season generously with salt and pepper.
  10. Preheat & Combine: Preheat your oven to 190°C (375°F). Stir the blanched green beans and 1/4 of the reserved crispy shallots into the mushroom sauce. Taste and adjust seasoning if necessary.
  11. Bake Initial Phase: Pour the mixture into the prepared 9x13 inch casserole dish. Bake for 15 minutes, or until the sauce is bubbling around the edges.
  12. Final Crisp: Remove the casserole from the oven. Gently top the dish with the remaining 3/4 of the crispy shallots. Return to the oven for a final 5–10 minutes, just until the topping is warm and the sauce is fully heated through. Serve immediately.