15 g butter
4 tablespoons olive oil
6 large red onions
1,2 litres vegetable stock
3 tablespoons balsamic vinegar
6 slices French baguette
1 tablespoon Dijon mustard
50 g grated Gruyere cheese
4 sprigs thyme
1 bay leaf
salt and pepper
Halve the onions and slice thinly. Heat the olive oil and butter in a pan and add the onions. Sweat them gently until soft, about 30 minutes.
Add the balsamic vinegar, thyme and bay leaf to the pan.
Add the stock to the pan and increase the heat. When the soup boils, turn down to a simmer and cook gently for a further 10 minutes.
Preheat the grill. Spread the mustard on the slices bread and top with the grated cheese. Transfer to an oven tray.
Place the tray under the grill for 2 minutes until the cheese is melted. Season the soup with salt and pepper.
Divide the soup between 2 bowls and place the grilled cheesy bread on top.
We, the Amsterdam Flavours chefs, hope you enjoy this recipe as much as we do. If you have any questions on how to prepare it or just want to send us your feedback, you can reach us here Contact Amsterdam Flavours