This dish is rich, and the carmelized onion jam is the ideal showcase for beautiful, aromatic truffles. For anything involving truffles I like to look at where they are hunted: France, Spain, Italy, Australia, and some
small quantities now in Napa Valley.
Let’s talk Cab! What a perfect pairing. Steak, truffles, Cabernet Sauvignon? Done. Cabernet Sauvignon that grows on the valley floor can sometimes be more fruit-forward, consider something coming from Mountain AVAs or blended with Cabernet Franc, something that will add depth and a secondary savory note.
Even consider Syrah from Napa, France, or Australia (where the varietal is referred to as Shiraz). The syrah grape has a great natural meatiness, and black pepper note that will add beautiful savory notes to every bite of this dish.
Cheers!