Boston Bean Soup with Watercress

I've been loving Lindsey Bareham's cookbook Just One Pot, which I picked up from the library here. Since I literally have one pot, this cookbook has been a lifesaver.

I made Boston Bean Soup with Watercress for dinner last night and we are having leftovers for lunch today. Today, when I took this picture, we didn't have any watercress left, so I used fresh parsley from the garden. It was sunny and warm outside, so we ate at the wrought iron table and chairs in the back courtyard.

2 T olive oil
5 oz bacon strips or pancetta, chopped
1 large red onion, finely chopped
2 plump garlic cloves, finely chopped
3 carrots, finely chopped
2 celery sticks, with leaves if possible, finely sliced
1/2 T flour
1 T smooth Dijon mustard
14-oz can chopped tomatoes
14-oz chicken broth or 1 chicken stock cube dissolved in 14 oz boiling water
squeeze lemon juice
1/2 t Tabasco sauce
14-oz can cannellini beans, drained and rinsed
3 oz watercress
4 T grated Parmesan cheese
salt and freshly ground pepper

Heat the oil in a spacious, heavy-based saucepan over medium-low heat. Add the pancetta or bacon until beginning to crisp. Stir in the onion and cook for about 6 minutes. Add the garlic and carrots. Season lightly with salt and generously with pepper. Cover and cook for 5 minutes, stirring occasionally, adjusting the heat so that the vegetables sweat rather than brown.

Add the celery and leaves to the pan. Cook for a minute or two, remove the lid, and sift the flour over the top. Stir until it disappears. Now stir in the mustard, tomatoes, a little of the stock, a squeeze of lemon juice, and the Tabasco. Bring to a boil, gradually adding the rest of the stock. Add beans, return to a simmer and cook for 10 minutes or until the vegetables are tender.

Taste and adjust the seasoning. Finely chop the watercress. Just before serving, stir in the watercress and serve each portion with a spoonful of Parmesan cheese and either a drizzle of olive oil or dash of freshly ground black pepper.