Ingredients:

  • 4 large shallots, thinly sliced
  • 3 cups neutral frying oil (Vegetable, canola, or grapeseed)
  • 1/2 tsp fine sea salt
  • 5 lbs fresh green beans, trimmed (Haricots Verts or French-style)
  • Water and ice, as needed (for blanching)
  • 4 Tbsp unsalted butter, divided
  • 8 oz cremini mushrooms, sliced thinly
  • 4 Tbsp all-purpose flour
  • 1 cup chicken or vegetable stock, low sodium
  • 1 cup whole milk
  • 1/2 cup heavy cream
  • 1/4 cup freshly grated Parmesan (optional)
  • 1/2 tsp garlic powder
  • Pinch freshly grated nutmeg
  • Kosher salt and black pepper, to taste

Instructions:

  1. Thinly slice the shallots. Pat them completely dry with a tea towel; moisture is the enemy of crispiness.
  2. Heat the oil in a Dutch oven to 325°F (160°C). Fry the shallot slices in batches, stirring constantly, until deeply golden brown and crispy (about 3–5 minutes per batch).
  3. Remove shallots with a slotted spoon or sieve and immediately spread them onto a paper-towel-lined baking sheet. Sprinkle generously with salt immediately. Reserve the remaining frying oil.
  4. Bring a large pot of salted water to a rolling boil. Add the trimmed green beans and cook for 3–4 minutes until bright green and tender-crisp (al dente).
  5. Immediately drain the beans and plunge them into an ice bath to stop the cooking process and lock in the colour. Drain thoroughly and set aside.
  6. Melt 2 Tbsp of butter in a large skillet over medium-high heat. Add the sliced mushrooms and sauté until they have released their liquid and browned beautifully (about 8 minutes). Remove from the skillet and set aside.
  7. Reduce the heat to medium-low. Add the remaining 2 Tbsp of butter to the skillet. Once melted, whisk in the flour to form the roux. Cook the roux for 1–2 minutes, stirring constantly.
  8. Slowly whisk in the warmed chicken stock until incorporated. Then gradually whisk in the milk and heavy cream. Bring to a gentle simmer, whisking frequently until the sauce thickens enough to coat the back of a spoon.
  9. Remove from heat. Stir in the Parmesan, garlic powder, nutmeg, salt, and pepper. Fold the reserved sautéed mushrooms back into the sauce.
  10. Preheat oven to 375°F (190°C). Gently fold the blanched green beans into the prepared mushroom sauce. Transfer the mixture to the prepared casserole dish.
  11. Bake uncovered for 15 minutes.
  12. Remove the casserole from the oven. Reserve half of the crispy shallots and scatter the remaining half over the top. Return to the oven for a final 10–15 minutes, or until bubbling hot.
  13. Allow the casserole to rest for 5 minutes before serving. Sprinkle the reserved fresh, crispy shallots over the top just before serving.