Tuna Pasta
["3 Tbsp. olive oil", "4 slices sweet onion (thin)", "4 slices red onion (thin)", "1/2 lb. tuna, cut into 1/2-inch cubes", "2 small tomatoes, sliced", "1/4 c. black olives, sliced", "2 Tbsp. basil (fresh), minced", "2 tsp. garlic, minced", "salt and pepper to taste", "1/4 lb. linguine", "2 Tbsp. capers, drained", "Italian parsley sprigs for garnish"]
["Heat oil in heavy medium skillet over medium-low heat.", "Add onions and cook until translucent, stirring occasionally, about 5 minutes.", "Add tuna, tomatoes, olives, basil, garlic, salt and pepper; cook until fish is opaque, stirring often, about 9 minutes."]
["olive oil", "sweet onion", "red onion", "tuna", "tomatoes", "black olives", "basil", "garlic", "salt", "linguine", "capers", "Italian parsley"]