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5 from 2 votes

Green bean casserole

Green bean casserole is a quintessential Thanksgiving side dish. Topped with crispy onions it is totally irresistible!
Prep Time20 mins
Cook Time1 hr
Total Time1 hr 20 mins
Course: Side Dish
Cuisine: American
Author: Lucy Parissi


  • 6 tbsp unsalted butter plus more to butter the dish
  • 600 g | 1.3lbs green beans trimmed
  • 400 g | 14oz chestnut button mushrooms halved or quartered
  • 1 large yellow onion peeled and finely diced
  • 240 ml | 1 cup whole milk
  • 120 ml | 1/2 cup vegetable stock I used Kallo stock cube
  • 2 heaped tbsp plain flour
  • 1 tbsp French’s yellow mustard
  • 1 tsp Worcestershire sauce
  • 1/2 tsp soy sauce
  • 60 g | 2oz grated Parmesan cheese
  • 3 tbsp French’s crispy onions finely ground
  • 3 tbsp French’s crispy onions to top
  • salt and freshly ground pepper to season


  • Blanch the green beans in boiling water for about 5 minutes then drain and plunge into a bowl of ice water until cooled. Drain and set aside.
  • Preheat the oven to 190C (375F).
  • Melt two tablespoons of the butter in a large skillet or frying pan. Sauté the onion until soft - 4-5 minutes.
  • Add the mushrooms and cook, stirring often, for a further 8 minutes. Season with salt and pepper and transfer to an ovenproof baking dish.
  • Add the remaining butter to the pan. Once butter melts, whisk in the flour to make a roux. Cook, stiring, for a couple of minutes.
  • Gradually stir in the milk and vegetable stock, whisking until the the mixture thickens. Stir in the mustard, Worcestershire and soy sauce. Check the seasoning and adjust if necessary. Cool completely.
  • Mix with the green beans and mushrooms, stirring thoroughly to combine.
  • Sprinkle with the ground crispy onions and Parmesan.
  • Cook, covered with foil, for about 50 minutes until bubbling.
  • Uncover and cook for a further 10 minutes.
  • Serve topped with crispy onions.


If preparing the dish in advance, follow the method until step 7, chill in the fridge overnight then top with the Parmesan and ground crispy onions just before baking.