Ingredients:

  • 500 ml Vegetable Oil (or Canola oil), for frying
  • 300 g Shallots (about 6 large, thinly sliced into rings)
  • 30 g All-Purpose Flour (1/4 cup)
  • 1/2 tsp Fine Sea Salt
  • 900 g Fresh Green Beans (2 lbs), trimmed
  • Coarse Salt, to blanch
  • 60 g Unsalted Butter (4 tbsp)
  • 340 g Cremini Mushrooms (12 oz), thinly sliced
  • 2 cloves Garlic, minced
  • 1 tsp Fresh Thyme Leaves
  • 60 g All-Purpose Flour (1/2 cup)
  • 120 ml Chicken or Vegetable Stock (1/2 cup), warm
  • 700 ml Whole Milk (3 cups), warm
  • 1 tsp Worcestershire Sauce
  • 1/4 tsp Freshly Grated Nutmeg
  • Kosher Salt and Freshly Ground Black Pepper, to taste
  • 60 g Grated Parmesan Cheese (1/2 cup) or Gruyère

Instructions:

  1. Toss the thinly sliced shallots with the 1/4 cup of flour and salt. Ensure they are evenly coated.
  2. Heat the oil in a heavy-bottomed pot to 160°C (320°F). Use a thermometer for accuracy.
  3. Fry the shallots in batches, stirring occasionally, until deeply golden brown (about 5-7 minutes per batch).
  4. Remove the shallots with a slotted spoon and spread them immediately onto a wire rack lined with paper towels. Season lightly with additional salt immediately. Set aside. Reserve 2-3 tablespoons of the frying oil.
  5. Bring a large pot of salted water to a rolling boil. Drop the trimmed green beans in and cook for 3-5 minutes until bright green and slightly tender-crisp (al dente).
  6. Immediately drain the beans and plunge them into an ice bath to stop the cooking process. Drain well and set aside.
  7. Preheat oven to 190°C (375°F). Return the heavy pot to the hob. Add the butter (or 2 tbsp of the reserved shallot oil) and melt over medium heat. Add the sliced mushrooms and cook until all liquid has evaporated and the mushrooms are deeply browned (about 8-10 minutes). Add the minced garlic and thyme; cook for 1 minute until fragrant.
  8. Sprinkle the 1/2 cup of flour over the mushroom mixture. Stir continuously for 2 minutes to cook out the raw flour taste, forming a roux.
  9. Slowly whisk in the warm stock until smooth. Then, gradually whisk in the warm milk. Continue stirring until the sauce thickens significantly (it should coat the back of a spoon).
  10. Stir in the Worcestershire sauce and nutmeg. Season generously with salt and pepper. Remove from heat.
  11. Place the blanched green beans into the 9x13 inch baking dish. Pour the creamy mushroom sauce over the beans. Stir gently to coat everything evenly.
  12. Sprinkle half of the grated Parmesan (or Gruyère) over the top of the beans.
  13. Bake (uncovered) for 20 minutes, until the sauce is bubbly and the edges are lightly browned.
  14. Remove the casserole from the oven. Sprinkle the remaining Parmesan and approximately two-thirds of the crispy shallots over the top.
  15. Return to oven and bake for a final 5 minutes, just until the cheese is melted and the shallots are hot (do not overbake).
  16. Garnish immediately with the reserved fresh crispy shallots just before serving for maximum crunch.