Ingredients:

  • 1 kg (2.2 lbs) Fresh Green Beans (Haricots Verts or French-cut), ends trimmed
  • 3 L (12 cups) Water
  • 1 Tbsp (15 ml) Kosher Salt (for blanching)
  • 80 g (6 Tbsp) Unsalted Butter, divided
  • 120 g (4 oz) Smoked Bacon or Pancetta, diced
  • 1 medium Yellow Onion, finely diced
  • 2 cloves Garlic, minced
  • 60 g (½ cup) All-Purpose Flour
  • 700 ml (3 cups) Whole Milk, warmed slightly
  • 120 ml (½ cup) Chicken or Vegetable Stock (low sodium)
  • 1 tsp (5 ml) Dijon Mustard
  • 2 tsp (10 ml) Onion Powder
  • ½ tsp (2.5 ml) Garlic Powder
  • ¼ tsp Freshly Grated Nutmeg
  • 1 tsp Black Pepper, freshly ground
  • Salt to taste
  • 180 g (1.5 cups) Sharp Cheddar or Gruyère Cheese, grated
  • 120 g (4 oz) Crispy Fried Shallots or Onions
  • 60 g (½ cup) Panko Breadcrumbs (optional)
  • 1 Tbsp (15 g) Unsalted Butter, melted (if using Panko)

Instructions:

  1. Blanch the Beans: Bring salted water to a rolling boil. Drop the trimmed green beans in for exactly 3–4 minutes until bright green and tender-crisp (al dente).
  2. Shock the Beans: Immediately transfer the beans to an ice bath to halt the cooking process. Drain well and set aside.
  3. Render the Bacon: In a large skillet, melt 1 tablespoon of butter and add the diced bacon/pancetta. Cook over medium heat until crispy. Remove the bacon with a slotted spoon and set aside, reserving 2 tablespoons of the rendered fat in the pan.
  4. Sauté Aromatics: Add the remaining 5 tablespoons of butter to the skillet with the reserved fat. Once melted, add the diced yellow onion and sauté until soft and translucent (about 5 minutes). Add the minced garlic and cook for 1 minute until fragrant.
  5. Create the Roux: Sprinkle the flour over the butter mixture. Cook, stirring constantly, for 2–3 minutes until a smooth, pale paste forms. Do not rush this step.
  6. Whisk in Liquids: Slowly whisk in the warmed milk, followed by the stock, ensuring no lumps form. Bring the mixture to a gentle simmer, stirring frequently, until the sauce thickens considerably (about 5–7 minutes).
  7. Season and Finish Sauce: Remove the skillet from the heat. Stir in the Dijon mustard, nutmeg, onion powder, garlic powder, salt, and pepper. Then, gently fold in the grated cheese until fully melted and smooth. Taste and adjust seasoning.
  8. Combine: Gently fold the blanched green beans and the reserved crispy bacon into the finished sauce.
  9. Initial Bake: Pour the mixture into a prepared 9x13 inch baking dish. Bake in a preheated oven at 190°C / 375°F for 20 minutes, or until the mixture is bubbling around the edges.
  10. Add Topping: Combine the crispy fried onions/shallots (and panko breadcrumbs, if using). Scatter evenly over the casserole.
  11. Final Bake: Return to the oven for an additional 8–10 minutes, or until the topping is golden brown and the interior is piping hot.
  12. Rest and Serve: Allow the casserole to rest for 5–10 minutes before serving.