Bag of veg - ideas pleeeeaasseee!!

You could make a soup from the parsnip.

Or, if you can't use any of the stuff with your meals this week (Cauliflower cheese, cabbage as a veg, roast or mashed parsnips?) then why not freeze them?

Parsnip, peel & chop then blanch in boiling water (ie just bring water to boil then remove from heat and drain)

Cut up cauli into florets and parboil as above.

Chop cabbage and do the same.

When drained and cooled, divide into usable portions and freeze in plastic bags.

Then, when you want to use them, you can add straight to boiling water, or steam from frozen Or put the parsnips in a roasting tin with oil and roast.

Curried Parsnip soup for the freezer?

Chop and fry and onion and some curry powder/garam masala. When softened add peeled and chopped parsnip, cook for a few minutes then cover with water or stock. Cook until soft. Add a grated apple (no need to peel) and seasoning. Puree and check seasoning. This is delicious, and popular with children as it's quite sweet.

Cauliflower you could blanch and freeze, I should think, or make a cauliflower cheese and freeze that?

Alternatively, as they're fresh, both would keep in the fridge until next week (cooked or not) and they are both very nice in a vegetable dahl. Fry and onion and some curry powder/garam masala (again!). Add the prepared veg and some red lentils. Cover with water and cook until lentils and veg are soft and of a porridgey consistency. Chech seasoning (Garam Masala doesn't need cooking out, unlike most curry powders, so add a bit more now if you want more curry flavour. It's also not spicy, so add some chilli if you like it to have more kick).
Serve with rice/poppadoms/naan breads (I make my own or buy and freeze when reduced or on BOGOF) and plain yogurt if you like. Thinly sliced raw onion and tomatoes go well too.

Not sure about freezing cabbage, but the following recipes work for any kind of cabbage (red/white/green) -

Coleslaw

Shred/grate/thinly slice/mix any combination of these vegetables: cabbage, carrot, onion, spring onion, apple, bean sprouts, celeriac, raw beetroot, kohlrabi, raw turnip and mix in either a vinaigrette dressing, or a mayo based one. To save money and calories I mix jarred mayo with plain yogurt and a bit of lemon juice or cider vinegar. If you have it a tsp of maple syrup goes suprisingly well!
This keeps well in the fridge and goes with lots of meals or in sandwiches.

Casseroled cabbage
Slice and onion and the cabbage. Add a little oil, some orange juice or red wine or even gin to prevent drying out. Caraway seeds and garlic go well too. (Prob wouldn't put the seeds with the gin). Cover and cook in low/medium oven when something else is on, especially jacket potatoes and meat, because it goes very well with those, or cook in slow cooker.
Again this keeps and reheats well.

HTH

Hazel