Mixed vegetables can be cooked in a pressure cooker to save time.  Bring the pressure cooker up to pressure and cook for 8 minutes.  Alternately the vegetables can be cooked the day before and then used in the crumble.  

Cooks Know How: Vegetables such as celeriac and butternut squash are touch and hard when raw.  On cooking they soften and mix together easily.  The leeks and courgettes also become softer and therefore more can be eaten.  The dietary fibre in the vegetables still remains after the cooking process. Calcium, vitamin A, vegetable proteins are also retained making the vegetable assortment very healthy.  The topping provides starchy carbohydrate from the flour and fat from the margarine.  Cheese provides high biological value protein additional to the vegetable proteins in the base. Flavours are enriched by the houmous and the sprinkled sea salt crystals. Textures come from the poppy seed and sunflower seeds. This recipe is a good main course for vegetarians and a great side dish to roast meats, steak or fish.  Peeling, chopping, boiling, rubbing in, grating and baking all combine to produce a worthy dish to use seasonal autumn and winter vegetables.