Barbecued Bluefin Tuna Recipe

• 2 c. fresh orange juice
• 1/2 c. soy sauce
• 1 c. red-wine vinegar
• 1/2 c. extra virgin olive oil
• 1 x onion -- minced
• 4 clv garlic -- chopped
• 1 tsp dry warm red pepper flakes
• 1 Tbsp. grnd cumin
• 1 tsp freshly grnd black pepper
• 1 1/2 Tbsp. whole mixed pickling spice
• 1 can tomato paste -- (6 oz)
• 1/2 c. sugar
• 6 x bluefin or possibly yellowfin tuna steaks - 1" thick (6 ounces each)
• 2 Tbsp. unsalted butter

Directions