Green bean casserole

Ingredients

• 450 g (1 pound)green beans
• 225 g (½ pound)mushrooms
• 60 g (1 cup)crispy fried onions
• 25 g (1 ounce)butter, for frying the mushrooms
• 50 g (2 ounces)butter, for the sauce
• 50 g (4½ tablespoons)plain flour
• 480 ml (2 cups)milk
• 100 g (¾ cup)grated cheese
• ½ teaspoonsalt
• ¼ teaspoonblack pepper

Instructions

1. 1

   Prepare the beans

   Wash the green beans, trim off the ends and cut them into lengths of 5–7.5 cm (2–3 inches).

2. 2

   Slice the mushrooms

   Wipe the mushrooms with a damp cloth and slice them thickly, into 4–6 slices each depending on their size.

3. 3

   Grate the cheese

   Grate the cheese using the largest holes on your grater.

4. 4

   Blanch the beans

   Put the prepared beans in a pan of lightly salted water and bring it to the boil. Boil for 3 minutes, then run the beans under cold water straight away to stop them cooking.

5. 5

   Brown the mushrooms

   Melt the butter for frying in a frying pan, then add the sliced mushrooms. Fry over a medium heat for 4–5 minutes, until nicely browned.

6. 6

   Combine vegetables

   Drain the beans and transfer them to a casserole dish. Stir in the mushrooms and set the dish aside while you make the sauce.

7. 7

   Make the sauce

   Melt the sauce butter in a saucepan over a medium heat. Stir in the flour, salt and pepper, mixing well to remove any lumps.

8. 8

   Thicken the sauce

   Add the milk and stir over a medium heat for 3–4 minutes, until the sauce thickens enough to fall slowly from a spoon.

9. 9

   Add the sauce

   Stir the sauce into the beans and mushrooms in the casserole dish.

10. 10

    Top with cheese

    Sprinkle the grated cheese evenly over the top.

11. 11

    Bake the casserole

    Bake in an oven preheated to 200°C (400°F) for 20–25 minutes, until the cheese has melted and turned golden.

12. 12

    Add the onions

    Sprinkle the crispy fried onions over the casserole and bake for a further 2–3 minutes to warm them through.

13. 13

    Serve hot

    Serve hot as a side dish with your choice of protein.

What is green bean casserole?

Green bean casserole is an American baked side dish built around green beans in a creamy sauce, often finished with a crisp topping. It is commonly served at holiday meals, but its straightforward ingredients also suit a weeknight table.

This version uses fresh beans, browned mushrooms and béchamel rather than relying on a prepared soup. Cheese adds a golden top, while fried onions bring the final crunchy contrast.

Nutrition and macros by portion

The nutrition label shows one serving as written: 243 calories, 8g protein, 16g carbs, 16g fat.

The beans and flour provide most of the carbohydrates, while butter, milk, cheese and fried onions contribute much of the fat. Milk, cheese and mushrooms provide some protein. Serve a moderate portion with a protein-rich main and another vegetable to balance the plate.

Fresh beans and mushrooms

Green beans: cutting them into similar lengths helps them cook evenly and makes the casserole easier to serve. A short boil softens them slightly while leaving them ready for the oven.

Mushrooms: thick slices hold their shape through frying and baking. Browning them first develops colour before they are stirred into the sauce.

Getting the béchamel smooth

Flour and butter: stir them together thoroughly before adding the milk, breaking up any lumps as you go. Add the milk and keep stirring while the sauce thickens over a medium heat.

Consistency: the finished sauce should fall slowly from a spoon, rather than run like milk. It will coat the vegetables and continue to settle around them in the oven.

Texture and doneness

Blanching: boiling the beans for 3 minutes gives them a head start, and rinsing them under cold water stops that cooking. Drain them well so excess water does not thin the sauce.

Baking: look for melted, golden cheese as the cue that the casserole is ready. The onions go on near the end so they warm through without spending the whole bake in the oven.

Timing the stages

Preparation: trim the beans, slice the mushrooms and grate the cheese before starting the cooking. Having these ready makes it easier to move from blanching to assembling without interruption.

Sauce and bake: make the béchamel after the vegetables are in the casserole dish, then bake for 20–25 minutes. Allow another 2–3 minutes after adding the crispy onions.

Serving the casserole

As a side: serve it hot alongside your choice of protein, as the recipe suggests. It also fits naturally on a holiday table with other vegetable and potato sides.

For a balanced plate: pair a portion with a protein-rich main and another vegetable or salad. The casserole is creamy and substantial, so a fresh or simply cooked accompaniment can round out the meal.

Recipe notes & tips

• Cut the beans into even lengths so they blanch at a similar rate.
• Rinse the beans under cold water as soon as the 3-minute boil is over.
• Let the mushrooms brown over a medium heat before stirring them into the beans.
• Stir continuously as the milk goes into the flour mixture to help keep the sauce smooth.
• Drain the beans well before assembling the casserole.
• Add the fried onions only for the final 2–3 minutes of baking.

Variations

• Use another cheese: choose a cheese that melts well for a slightly different flavour.
• Add garlic: stir a little chopped garlic into the mushrooms as they fry.
• Use frozen beans: thaw and drain them well before assembling the casserole.
• Change the topping: use extra grated cheese in place of some of the fried onions.
• Add herbs: stir chopped thyme or parsley into the sauce for a fresh herbal note.

Common mistakes to avoid

• Overcooking the beans: boil them for just 3 minutes, then rinse under cold water to stop them cooking.
• Watery casserole: drain the beans thoroughly before adding them to the dish.
• Pale mushrooms: fry them over a medium heat until browned before combining them with the beans.
• Lumpy sauce: mix the flour thoroughly into the melted butter before adding the milk.
• Thin sauce: keep stirring over a medium heat for 3–4 minutes, until it falls slowly from a spoon.
• Soggy onions: add the crispy fried onions for only the last 2–3 minutes of baking.

How to store

Refrigerate leftovers in a covered container and eat within 3 days. Reheat until piping hot in the oven or microwave; the fried onions may soften after storage.

Frequently asked questions