Ocado Portobello Mushrooms. Portobello mushrooms are light-beige to cinnamon brown in colour with a slightly nutty flavour and a firm, meaty texture. Serving Suggestion Ideal for stuffing or slicing thickly, griddle and pour over creamy peppercorn sauce as a delicious side dish. Great for soups and stews or adding to omelettes and stir-fries. Pairs well with poultry and pastas.