Make up the veg stock and add the rosemary and tarragon. Allow it to steep while you prepare the rest of the veg.
In a flame proof casserole dish, gently sweat the leeks, onions, garlic and shallots in a few table spoons of oil.
After about ten minutes, add the tomato purée, carrots and cornflour and give it all a good stir.
Pour your wine into your steeped stock, then slowly pour all of the liquid into the casserole dish, stirring as you go.
Add the mushrooms on top of the veg, don’t worry if they aren’t submerged under the stock with the other veg.
Put the dish in the oven at 180 C. Stir it every 15 mins or so for the first half hour until the mushrooms have reduced in size and are incorporated into the rest of the casserole.
