Grilled Beef Bourguignon

Name: Grilled Beef Bourguignon
Ingredients: Two 8-ounce rib-eye steaks; Kosher saltand freshly cracked black pepper; 2 teaspoons all-purpose flour; 2 tablespoons vegetable oil; 4 tablespoons unsalted butter; 1 yellow onion, large-diced; 8 ounces oyster mushrooms, halved; 1 parsnip, peeled and medium-diced; 5 sprigs thyme; 2 tablespoons tomato paste; Half 750-ml bottle rich red wine(preferably from Burgundy); 1/2 cup beef stock, plus more as needed; 2 tablespoons dry sherry; 1 lemon, juiced