Preheat the oven to 400 degrees F. Place half the oil in a pot set over medium heat. Add the onion and garlic and cook 3–4 minutes. Add the tomatoes, stock, wine and sugar and simmer 10 minutes, or until the tomatoes soften. Stir in artichokes, basil, olives, salt and pepper; remove from the heat.
Set halibut in a parchment paper-lined baking dish. Drizzle and sprinkle with remaining olive oil, lemon juice, salt and pepper. Bake 15 minutes, or until cooked through. Return sauce to a simmer. Divide fish among plates, top with the sauce and serve.