sheet pan roasted fish and vegetables - TK

Ingredients

• 16 ounces halibut, cod or other firm white fish
• 1/2 pound small potatoes (such as red potatoes), cut in half or quarters if they're large
• 1 onion, cut in quarters and petals slightly separated so you have 8-10 pieces
• 1 pint campari tomatoes (or cherry tomatoes)
• 1 pint baby portobello mushrooms, stems trimmed and cut in quarters
• 1 lemon, cut in half
• 2-3 tablespoons olive oil
• 2 teaspoons course sea salt
• 1 teaspoon freshly ground black pepper
• 1 large sprig rosemary, leaves removed and roughly chopped
• White balsamic vinegar (optional)
• Small handful chopped parsley (optional)