Portmeirion Botanic Garden Covered Vegetable Dish: SERVING WITH STYLE: This Botanic Garden 3 pint covered casserole dish from Portmeirion is available in the sweet pea motif. TOP TIER MATERIAL: Made from strong porcelain it can go from freezer to oven and, because of its inherent beauty, it can then go straight to the table - perfect to cook and serve.