In a saucepan, heat the pure olive oil until shimmering. Add the shallot and garlic and cook over moderate heat, stirring, until softened, about 4 minutes. Stir in the Dijon mustard and half of the whole-grain mustard. Add the brandy and cook until nearly evaporated, about 3 minutes. Add the wine; simmer until reduced by half, about 10 minutes. Add the cream, Worcestershire sauce and reduced veal stock and simmer until thickened, about 15 minutes. Strain the mustard sauce into a heatproof bowl. Whisk in the remaining whole-grain mustard; season with salt and white pepper. Cover and keep warm.