Season tomato halves with sea salt and drizzle with 1 tbsp olive oil. Place a cast iron pan over medium-high heat. Sear tomato halves, seed side down, until a little charred. Transfer tomatoes to a roasting pan and drizzle with remaining 1 tbsp olive oil. Cover with aluminum foil. Roast in oven preheated to 400°F for 8 to 10 minutes. Before serving, top the tomatoes with a sprinkle of chopped parsley.