Ingredients

750g / 1.5lb green beans, trimmed and halved

2 large yellow onions, peeled, halved and thinly sliced (or 3 medium)

1/4 cup (35g) plain/all purpose flour

2 tbsp panko breadcrumbs

1/2 tsp salt

1/4 tsp black pepper

4 cups / 1 litre vegetable oil (for deep-frying, or peanut/canola oil)

3 tbsp (50g) unsalted butter

360g / 12 oz mushrooms, chopped into 1cm (1/3″) pieces

3/4 tsp salt

1/4 tsp black pepper

2 garlic cloves, minced

3 tbsp (35g) plain/all purpose flour

1 1/2 cups (375ml) vegetable or chicken broth/stock, low sodium

1/2 cup (125ml) heavy/thickened cream

Pinch of nutmeg (or sprinkle of freshly grated)

Instructions

Step 1: Boil the green beans for 3 minutes until just tender, then drain and run under cold tap water to stop cooking. Alternatively, you can steam the beans. Transfer to a clean tea towel and pat dry. Set aside.

Step 2: Prepare crispy onions by lining a tray with 3 to 4 layers of paper towels. Toss the sliced onions with flour, panko breadcrumbs, salt, and pepper.

Step 3: Heat about 2cm (3/4″) of oil in a heavy skillet over medium-high heat. Test the oil by dipping the end of an onion slice—it should sizzle immediately. Fry onions in small batches for 1 1/2 minutes until light golden brown, then transfer to the paper towel-lined tray in a single layer. Repeat with remaining onions and set aside to cool without covering.

Step 4: For the creamy mushroom sauce, melt butter in a skillet over medium-high heat. Add mushrooms and cook for 1 minute, then add salt and pepper. Cook until mushrooms start to soften, about 1 1/2 minutes. Add garlic and cook until golden, about 1 minute.

Step 5: Reduce heat to medium and stir in flour, mixing until flour is no longer visible. Gradually pour in half the broth while stirring constantly. Once smooth, add remaining broth and cream, stirring to combine. Add nutmeg and cook for 5 minutes, stirring regularly, until the sauce thickly coats the back of a wooden spoon.

Step 6: Preheat oven to 350°F (180°C, 160°C fan). Pour the green beans into the pot or a bowl, then stir in the mushroom sauce. Transfer mixture to a 2.5 quart (2.5 liter) casserole dish and smooth the surface.

Step 7: Sprinkle the crispy onions over the top (you may not use them all). Bake for 15 minutes until bubbling at the edges and onions turn deep golden. Check at 10 minutes to ensure onions don’t burn.

Step 8: Serve immediately and enjoy!

Tips & Variations

Use fresh, firm green beans for the best texture and flavor.

Try substituting panko with crushed cornflakes for a different crunch.

For a richer flavor, use chicken broth instead of vegetable broth.

You can prepare the crispy onions ahead and store them in an airtight container to keep them crunchy.

Add a handful of shredded cheddar cheese on top before baking for a cheesy twist.

FAQs

Can I use frozen green beans for this casserole?

Yes, frozen green beans work well. Just thaw and drain them thoroughly before using to avoid excess moisture in the dish.

How do I keep the onions crispy?

Fry the onions in small batches to avoid overcrowding, and spread them out on paper towels to cool without covering. Add them to the casserole just before baking and monitor the oven to prevent burning.