Preheat the oven to 375°. In a small skillet, heat the vegetable oil. Add the sage sprigs and fry over high heat until deep green and translucent, about 1 minute. Transfer to a paper towel-lined plate to cool. Season with salt.
Season the veal chops with salt and pepper and dust lightly with flour, patting off the excess. In a large skillet, melt 1 tablespoon of butter in the olive oil. Add half of the veal chops and cook over high heat, turning once, until golden brown, about 7 minutes. Transfer to a large baking pan and repeat with the remaining chops, lowering the heat to moderate.
Roast the veal chops for 15 minutes or until an instant-read thermometer inserted near the bone registers 140°.
Meanwhile, pour off the fat in the skillet. Add the remaining 1 tablespoon of butter and the shallots and cook over moderate heat until softened, about 3 minutes. Remove from the heat. Add the Cognac and boil over moderately high heat, scraping up any bits stuck to the bottom, until the pan is nearly dry, about 2 minutes. Add the cream and chicken stock and bring to a boil. Season with salt and pepper and boil over moderately high heat until reduced to 3/4 cup, about 15 minutes.
Strain the sauce into a saucepan, season with salt and pepper and whisk in the truffle butter over low heat until incorporated.
Transfer the veal to plates and spoon the sauce on top. Garnish with the fried sage sprigs and serve.
The crème anglaise can be refrigerated for up to 5 days.