Start by heating the butter over medium high heat and sauteing the shallots until translucent. Deglaze with red wine, add peppercorns, and reduce until most of the wine is gone.
Add the Veggie-Glace Gold and hot water stirring (with a whisk if you have one) constantly until the Veggie-Glace is dissolved. Simmer until the sauce has thickened enough to coat a spoon, approximately 6-8 minutes.
Add finely chopped parsley, stir, and serve over the sliced portobellos.