Ingredients:

  • 5 lbs (680 g) Fresh Green Beans, trimmed and snapped
  • 1 Tbsp (15 g) Kosher Salt (for blanching water)
  • 4 Tbsp (56 g) Unsalted Butter
  • 8 oz (225 g) Cremini (Baby Bella) Mushrooms, thinly sliced
  • 2 medium Shallots, finely diced
  • 2 cloves Garlic, minced
  • 4 Tbsp (30 g) All-Purpose Flour
  • 1 cup (240 ml) Low-Sodium Chicken or Vegetable Stock
  • 1 cup (240 ml) Whole Milk or Half-and-Half (room temperature)
  • 1 tsp (5 ml) Fresh Thyme leaves, chopped
  • 1/2 tsp (3 ml) Worcestershire Sauce
  • Pinch Freshly Grated Nutmeg
  • Kosher Salt and Freshly Ground Black Pepper, To taste
  • 6 oz (170 g) Crispy Fried Onions (store-bought standard)
  • 1/4 cup (30 g) Parmesan or Gruyère cheese (optional, finely grated)

Instructions:

  1. Preheat the oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish. Bring a large pot of salted water to a rolling boil. Add the trimmed green beans and cook (blanch) for 3-4 minutes until bright green and still al dente.
  2. Immediately drain the beans and plunge them into an ice bath to halt cooking and set the color. Drain thoroughly and set aside.
  3. Melt the butter in a large skillet over medium heat. Add the sliced mushrooms and cook for 5-7 minutes until they release moisture and start to brown. Season lightly. Add the diced shallots and sauté for 3 minutes until softened. Add the minced garlic and cook for 1 minute more.
  4. Sprinkle the all-purpose flour over the mushroom mixture (creating the roux). Stir constantly for 1-2 minutes to cook the raw flour taste out.
  5. Gradually whisk in the low-sodium stock until smooth, then slowly whisk in the room-temperature milk or half-and-half. Bring to a gentle simmer, whisking occasionally, until the sauce thickens enough to coat the back of a spoon (3-5 minutes).
  6. Stir in the fresh thyme, Worcestershire sauce, nutmeg, and adjust seasoning with salt and pepper. Remove from heat. Gently fold the blanched green beans into the creamy mushroom sauce until evenly coated.
  7. Pour the mixture into the prepared casserole dish. Sprinkle half (3 oz / 85 g) of the crispy fried onions and the optional grated cheese over the top. Bake for 15-20 minutes, or until the sauce is bubbly and the edges are golden.
  8. Remove the casserole from the oven. Sprinkle the remaining half (3 oz / 85 g) of the crispy fried onions evenly across the top. Return to the oven for a final 3-5 minutes, just until the topping is warmed through and lightly golden. Let rest for 5-10 minutes before serving.