Ingredients:

  • 2 lbs Fresh Green Beans (Haricots Verts preferred), trimmed
  • 1 Tbsp Coarse Salt (for blanching water)
  • 4 Tbsp Unsalted Butter, divided
  • 12 oz Cremini/Chestnut Mushrooms, sliced thinly
  • 2 medium Banana Shallots or Onion, finely minced
  • 2 cloves Garlic, minced
  • 4 Tbsp All-Purpose Flour
  • 1 cup Chicken or Vegetable Stock (low sodium), warmed
  • 1 cup Heavy Cream (35%+ fat)
  • 1 tsp Fresh Thyme Leaves, finely chopped
  • Pinch Freshly grated Nutmeg
  • Kosher Salt and Fresh Black Pepper, To taste
  • 3 large Banana Shallots (for homemade topping) OR 6 oz Store-bought Crispy Fried Onions
  • 2 cups Vegetable Oil (if making homemade topping)

Instructions:

  1. Prepare the Beans: Bring a large pot of heavily salted water to a rolling boil. Add the trimmed green beans and cook for exactly 3–4 minutes until bright green and tender-crisp (al dente).
  2. Shock the Beans: Immediately drain the beans and plunge them into a large bowl of iced water to stop the cooking process (this locks in the color and texture). Drain thoroughly and set aside.
  3. Sauté Mushrooms: Melt 2 Tbsp of butter in a skillet over medium-high heat. Add the sliced mushrooms and sauté until the liquid has evaporated and they are deeply browned and caramelized (about 8–10 minutes). Remove the mushrooms and set aside.
  4. Sauté Aromatics: Reduce the heat to medium. Melt the remaining 2 Tbsp of butter. Add the minced shallots and cook until softened (3–4 minutes). Add the minced garlic and cook for 1 minute until fragrant.
  5. Make the Roux: Whisk in the flour and cook, stirring constantly, for 1–2 minutes to cook out the raw flour flavor.
  6. Build the Sauce: Slowly pour in the warm stock while vigorously whisking to prevent lumps. Bring to a simmer, then reduce heat to low.
  7. Finish the Sauce: Stir in the heavy cream, thyme, nutmeg, and the reserved caramelized mushrooms. Season aggressively with salt and pepper. Simmer gently for 2–3 minutes until the sauce coats the back of a spoon. Taste and adjust seasoning.
  8. Assembly: Preheat oven to 375°F (190°C). Gently fold the blanched green beans into the cream sauce until fully coated. Pour the mixture into a prepared 9x13 inch casserole dish.
  9. Initial Bake: Bake uncovered for 15 minutes, allowing the sauce to bubble and thicken slightly.
  10. Prepare Topping (Optional Homemade Shallots): Heat 2 inches of oil in a small pot to 325°F (160°C). Carefully drop the sliced shallots into the oil and fry until golden brown and crisp (3–4 minutes). Drain them immediately on paper towels and season with salt. Skip this step if using store-bought topping.
  11. Final Bake: Remove the casserole from the oven. Sprinkle the crispy shallots (homemade or store-bought) evenly over the top. Return to the oven for a final 10–15 minutes until the topping is golden and the sauce is piping hot. Let the casserole rest for 5–10 minutes before serving.