Ingredients:

  • 3 large shallots, thinly sliced into rings
  • 1/4 cup all-purpose flour (for dredging)
  • 1/2 teaspoon salt (for dredging)
  • 2 cups vegetable or canola oil (for shallow-frying)
  • 1 1/2 lbs fresh green beans, trimmed
  • 1 tablespoon salt (for blanching water)
  • 4 tablespoons unsalted butter, divided
  • 8 oz cremini (Baby Bella) mushrooms, sliced
  • 2 cloves garlic, minced
  • 4 tablespoons all-purpose flour (for roux)
  • 1 cup chicken or vegetable stock (low-sodium preferred)
  • 1 1/2 cups whole milk
  • 1 teaspoon fresh thyme leaves
  • 1 teaspoon Worcestershire sauce
  • Pinch freshly grated nutmeg
  • Kosher salt and black pepper, to taste

Instructions:

  1. Toss the thinly sliced shallots with the 1/4 cup of flour and 1/2 tsp salt in a medium bowl until fully coated. Shake off excess flour.
  2. Heat the 2 cups of oil in a deep saucepan over medium-high heat until it reaches 350°F (175°C). Carefully add the shallots in batches (do not crowd the pan). Fry until deep golden brown and crisp, about 3–5 minutes.
  3. Remove shallots with a slotted spoon and immediately spread them onto a wire rack lined with paper towels. Season immediately with a pinch of salt. Set aside.
  4. Bring the stockpot of salted water to a rolling boil. Add the trimmed green beans and boil for exactly 4 minutes.
  5. Immediately drain the beans and plunge them into an ice bath to stop the cooking process. Drain thoroughly and pat dry. Set aside.
  6. Melt 2 tablespoons of butter in a large skillet over medium heat. Add the sliced mushrooms and sauté until they have released their liquid and are deeply browned and caramelized. Add the minced garlic and sauté for 1 minute more. Remove the mushroom mixture and set aside.
  7. Melt the remaining 2 tablespoons of butter in the same skillet. Whisk in the 4 tablespoons of flour until a smooth paste (roux) forms. Cook, stirring constantly, for 1–2 minutes until the roux smells slightly nutty.
  8. Gradually whisk in the cold chicken/vegetable stock until smooth. Slowly whisk in the whole milk. Continue stirring until the sauce thickens significantly and coats the back of a spoon (about 5–7 minutes).
  9. Stir the reserved mushrooms and garlic back into the sauce. Add the thyme, Worcestershire sauce, nutmeg, salt, and pepper. Taste and adjust seasoning as necessary.
  10. Gently fold the blanched green beans into the creamy mushroom sauce until fully coated.
  11. Pour the mixture into the prepared 9x13 inch casserole dish.
  12. Bake in a preheated oven at 375°F (190°C) for 15 minutes, until the sauce is bubbly and hot throughout.
  13. Remove the casserole from the oven. Evenly sprinkle about half of the reserved crispy shallots over the top. Return to the oven and bake uncovered for another 10 minutes, or until the topping is golden brown and the edges are aggressively bubbling.
  14. Let the casserole rest for 5–10 minutes before garnishing with the remaining crispy shallots just before serving.