Ingredients:

  • 4 large shallots (approx. 200g), thinly sliced into rings
  • 2 Tbsp (30g) all-purpose flour
  • 1/4 tsp (1g) fine sea salt
  • 2 cups (475ml) neutral oil (e.g., canola, vegetable oil) for frying
  • 2 lbs (900g) fresh green beans, trimmed
  • Coarse salt for blanching water
  • 4 Tbsp (60g) unsalted butter
  • 1 lb (450g) cremini (brown) mushrooms, thinly sliced
  • 1 small yellow onion or 2 small shallots, finely diced
  • 2 cloves garlic, minced
  • 1/4 cup (30g) all-purpose flour (for the roux)
  • 2 cups (475ml) chicken or vegetable stock (low sodium)
  • 1 cup (240ml) whole milk or half-and-half
  • 1/2 cup (120ml) heavy cream (double cream)
  • 1 tsp (5g) dried thyme
  • 1/4 tsp (1g) freshly grated nutmeg
  • Kosher salt and freshly cracked black pepper to taste

Instructions:

  1. Prep the Shallots: Toss sliced shallots with 2 Tbsp flour and 1/4 tsp salt.
  2. Fry the Shallots: Heat oil in a deep pan to 325°F (160°C). Fry the floured shallots in small batches until deeply golden brown and crisp (about 3-4 minutes per batch). Do not crowd the pan.
  3. Drain and Cool: Remove shallots immediately with a slotted spoon and spread them on a paper towel-lined tray. Season lightly with extra salt while hot. Set aside to cool and crisp up completely.
  4. Blanch the Beans: Bring a large pot of heavily salted water to a rolling boil. Drop in the trimmed green beans and cook for 4–5 minutes until tender-crisp (al dente).
  5. Shock the Beans: Immediately drain the beans and plunge them into an ice bath to halt cooking and set the vibrant green color. Drain thoroughly and set aside.
  6. Sauté the Mushrooms: Melt butter in the Dutch oven over medium heat. Add sliced mushrooms and sauté until they have released their liquid and browned deeply (about 8–10 minutes). Season lightly.
  7. Aromatics: Add diced onion (or shallots) and garlic to the pan and cook until soft and fragrant (about 3 minutes).
  8. Create the Roux: Sprinkle the 1/4 cup flour over the mushroom mixture. Cook, stirring constantly with a whisk, for 1–2 minutes until the paste smells nutty and slightly toasted.
  9. Whisk in Liquids: Slowly whisk in the cold stock until smooth. Once fully incorporated, slowly whisk in the milk and cream.
  10. Simmer and Season: Bring the sauce to a gentle simmer, whisking occasionally. Reduce heat and cook for 5–7 minutes until thickened. Stir in the thyme and nutmeg. Taste and adjust seasoning with salt and pepper.
  11. Combine: Preheat oven to 375°F (190°C). Gently fold the blanched green beans into the prepared mushroom sauce.
  12. Transfer: Pour the mixture evenly into the prepared casserole dish (2-quart/1.9L).
  13. Bake: Bake uncovered for 15–20 minutes, or until the sauce is bubbly and heated through.
  14. Finish and Serve: Remove the casserole from the oven. Immediately scatter the reserved crispy shallots evenly over the top. Serve hot.