1/2 (14.5-oz.) pkg. refrigerated piecrust 3 tablespoons unsalted butter, divided 2 tablespoons olive oil, divided 8 cups thinly sliced sweet onions (about 2 large) 1/3 cup Calvados or apple brandy 1 (15-oz.) pkg. pre-cooked beef roast au jus (such as Hormel) 1 (10-oz.) can beef consommé 8 ounces cremini mushrooms, stemmed and thickly sliced 1 cup chopped carrots (about 2 medium) 1 1/2 tablespoons chopped fresh thyme 3 tablespoons all-purpose flour 1/4 teaspoon kosher salt 4 (3-oz.) sourdough bread slices, torn into bite-size pieces 8 ounces Gruyère cheese, shredded (about 2 cups) Chopped fresh chives