Step 1

Preheat the oven to 200C/180C Fan /Gas 6.

Step 2

Transfer the onion and other vegetables to a roasting tin with the whole thyme sprigs and trickle over the olive oil. Roast the vegetables for 1 hour.

Step 3

Add the butter beans and ground allspice to the roasting tray and mix well, making sure that any dry parts are well coated in olive oil. Bake for a further 30 minutes.

Step 4

Cut the stem ends off the green beans. Cook in a pan of boiling salted water for 4 minutes. Remove and refresh in a bowl of iced water.

Step 5

Fold the green beans into the roasted vegetables. Season with salt and pepper and serve.