Fry off the chicken at a high heat in a generous drizzle of olive oil, then remove and put to one side, leaving the oil. If not using chicken for the recipe, just add your oil to the pan.
Add the onion, carrot and celery to the pan and simmer gently for 3-4 minutes to soften.
Sprinkle with the flour, the herbs and seasonings and stir until the flour soaks up the oil and coats the vegetables. Simmer lightly for a minute or so.
Add the white vermouth, turn the heat up to halfway, keep stirring until most of the liquid has gone. It won't take long.
Add the potatoes, swede, broccoli and cauliflower along with the stock. The liquid should just about cover the vegetables. If some are out of the water it's ok, they will shrink as they cook. Give it a stir and put on the lid. Keep on the hob, on a low - midway heat. Stir intermittently to prevent anything sticking to the bottom of the pan.
Whilst this cooks, you can make the dumplings. Add the flour, suet and butter to a bowl and use your fingers to work into a crumb. You can make dumplings with either just suet or just butter. I had a bit of both so went with that.
Grate and add the cheese, along with salt and pepper.
Make a well and add a little water at the time, working together until you have a solid dough that isn't wet or sticky, but is still mailable. (You can always add a little flour or water if it goes too much one way).
Spread the mustard over the dough and fold in lightly. Lightly will leave bright, yellow streaks, and concentrated pockets of flavour.
Separate the dough in 9-10 small balls and roll in a little flour.
Check on the stew. If the vegetables are completely soft you can move on, but give it some extra time to cook if needed. Stews taste so much better for patience.
Position the dumplings on top of the stew, being careful to space them out as they grow to about twice the size. Put the lid on and return the dish to the hob. Turn the oven and preheat it to 150
After 15 minutes you should see the dumplings have risen nicely. Take the lid off and pop the dish in the oven for 10-15 minutes, until the dumplings are all golden and crispy.
Leave for 10 minutes to meld, then serve in a bowl with a spoon. Snuggle up in a chair with your thick socks on and enjoy the ultimate in comfort food.
If you can leave some until the following day then I heartily recommend it. Like lasagne, this dish does well for a few hours to soak up.