1 6-pound first-cut brisket, (with the deckle, fatty edge, removed)
3 tablespoons Spanish paprika (Pimenton Vera), divided
2 teaspoons freshly ground black pepper
1 teaspoon kosher salt
3 tablespoons olive oil
4 medium onions, thinly sliced (about 3-4 cups)
2 tablespoons chopped garlic
2 cups Spanish dry sherry
2 cups low-sodium chicken stock
1 14-ounce can Muir Glen diced tomatoes
2 bay leaves
1 pinch saffron threads
2 teaspoons fresh thyme leaves
2 tablespoons sherry vinegar, or more to taste
Salt and freshly ground black pepper
1/2 cup pitted Spanish green olives