Half the shallots and cut each half into quarters. Fry in little olive oil on a medium-high heat until they begin to caramelise then move the onions to a casserole dish.
Next, stone and roughly chop the olives. Wipe the shitake and chestnut mushrooms with damp kitchen roll or cloth to remove any grit then chop into chunky pieces, either halves or into thirds depending on how sizable the mushrooms are. Place the olives and mushrooms in a frying pan with a little more olive oil and fry on a medium-high heat for 3 minutes until the mushrooms begin to brown a little.
Transfer the mushrooms and olives to the casserole dish.
Peel and finely chop the garlic and add to the casserole dish along with the sprigs of thyme and bay leaf. Give the ingredients a stir so that the garlic and thyme is distributed fairly evenly then, pour in the red wine. The wine should pretty much cover the other ingredients but if it is well off, add a bit more.
Bring to a boil and then turn down to simmer for around 20 minutes. The shallots should be soft and the mushrooms should have lost all their foamy texture.
While the mushrooms are cooking, in a small bowl make a roux by mixing together the flour and oil until smooth.
When cooked, remove the mushrooms and all other contents of the pan with a slotted spoon so that all that remains is the liquid. Set aside and keep warm.
Turn the heat up on the wine and let it simmer until it reduces by about a third. Then, add the roux a few drops at a time stirring continuously to avoid any lumps. Once all the roux has been added return the mushrooms and other ingredients to the casserole dish and stir to combine. Add a pinch of sugar and then taste before you start add any salt and pepper as the a la Grecque are incredibly salty.
To serve, remove the thyme sprigs and bay leaf and sprinkle with the chopped parsley.
Recipe by Figs & Fennel at http://www.figsandfennel.co.uk/mushroom-bourguignon/