Place a large saucepan over medium-high heat and coat with the oil. When hot, add the mushrooms, shallots, bay leaves, thyme, peppercorns, and coriander. Cook, stirring, until the natural moisture from the shallots and mushrooms is released and they begin to brown, about 10 to 15 minutes.

Sprinkle in the sugar, stirring to dissolve. Add the vinegar to deglaze the pan, scraping up the bits in the bottom with a wooden spoon. Add the wine and simmer, stirring occasionally, until the mushrooms are deep purple and the wine is almost totally cooked out, about 40 minutes.

Add the veal demi-glace and continue to simmer until the liquid is reduced by half, about 30 to 40 minutes.

Strain the sauce into a clean saucepan or container and discard the solids. Serve hot.