Ingredients:

  • 4 small/medium Shallots, thinly sliced
  • 1 cup Buttermilk (or whole milk)
  • 1/2 cup All-Purpose Flour (for coating)
  • 2 Tbsp Cornstarch (or rice flour)
  • 1 tsp Kosher Salt (for coating)
  • 4 cups Neutral Oil (Peanut, Canola), for deep frying
  • 1 1/2 lbs Fresh Haricots Verts (fine green beans), trimmed
  • Kosher Salt, as needed (for blanching water)
  • 4 Tbsp Unsalted Butter
  • 10 oz Cremini (Chestnut) Mushrooms, sliced thinly
  • 3 medium Garlic Cloves, minced
  • 1/4 cup All-Purpose Flour (for roux)
  • 2 cups Chicken or Vegetable Stock (low sodium), warmed
  • 1/2 cup Heavy Cream (Double Cream)
  • 1 tsp Fresh Thyme Leaves, finely chopped
  • Pinch Ground Nutmeg
  • 1/4 tsp White Pepper
  • 1 tsp Kosher Salt (for sauce, or to taste)
  • 1/4 cup Parmesan Cheese (optional), freshly grated

Instructions:

  1. Soak Shallots: Place thinly sliced shallots in buttermilk for 15-20 minutes. This helps the coating adhere.
  2. Heat Oil: Pour oil into the Dutch oven and heat to 350°F (175°C). Use a thermometer to maintain temperature stability.
  3. Coat Shallots: Whisk together the 1/2 cup flour, cornstarch, and 1 tsp salt. Drain the shallots well (do not rinse) and toss them thoroughly in the flour mixture, shaking off any excess.
  4. Fry: Fry the shallots in batches, stirring occasionally, until deeply golden and crisp (about 4–6 minutes per batch).
  5. Drain and Season: Remove shallots with a slotted spoon and place them immediately on a paper towel-lined tray. Sprinkle lightly with salt while still warm. Set aside to cool completely.
  6. Boil and Blanch: Bring a large pot of salted water to a rolling boil. Drop the trimmed beans into the boiling water and cook for exactly 3–4 minutes until bright green and just tender-crisp (al dente).
  7. Shock: Immediately drain the beans and plunge them into the ice bath to stop the cooking process and set the vibrant green colour. Drain thoroughly and set aside.
  8. Sauté Mushrooms: Melt 2 Tbsp of butter in a heavy-bottomed saucepan over medium-high heat. Add the sliced mushrooms and sauté until they have released their liquid and browned deeply (about 8–10 minutes). Remove mushrooms and set aside.
  9. Make the Roux: Reduce heat to medium. Add the remaining 2 Tbsp of butter to the saucepan. Once melted, whisk in the 1/4 cup flour until a smooth paste (roux) forms. Cook, stirring constantly, for 2 minutes to cook out the raw flour taste.
  10. Build the Sauce: Slowly whisk in the warm stock, making sure to scrape the bottom of the pan to prevent lumps. Bring the sauce to a gentle simmer; it will thicken significantly.
  11. Finish the Sauce: Reduce heat to low. Stir in the heavy cream, garlic, thyme, nutmeg, white pepper, and salt. Return the sautéed mushrooms to the sauce. Taste and adjust seasoning.
  12. Combine: Preheat oven to 375°F (190°C). Gently fold the blanched green beans into the mushroom sauce mixture.
  13. Transfer: Pour the mixture into the prepared 9x13 inch baking dish. If using, sprinkle the Parmesan cheese over the top.
  14. Bake: Bake for 20–25 minutes, or until the sauce is bubbling around the edges. The internal temperature should be piping hot.
  15. Topping: Remove the casserole from the oven. Gently scatter the crispy shallots over the top just before serving to maintain maximum crunch.