with fresh veg I blanche it for 2-3 minutes ( dunk in boiling water and par boil ) then throw into iced water and freeze in portion sized bags, this lasts you much longer and when re using i just check the veg complete with freezer bag into hot water to cook.
I find a good fist sized portion will do
Also buy things like butternut squash, they last for ages just hanging around your cupboard. Sweet potatoes last forever too!
a great simple meal for veg only is stuffed corguettes, i love this and its really filling. Here is a reciepe i use:
boil whole courgettes for 15 mins ish, then slice down the middle and scoop out the guts to make a boat ( mind your fingers tis hot! )
for the filling i finely chop the courgette innards, red onion, add sweetcorn, butternut squash - fry this off in that squirty spray oil thing for about 10 mins on low to soften, add your spices as you please - garlic, pepper, whatever you like.
Crack 2 eggs and throw the yolks ( so tasty
but NO ) so you just have the whites
chuck the egg white in with all your chopped up bits, and add to your little courgette canoes
oven bake at 180 for half an hour BOOM this will fill you up a treat and also its fab cold for lunch the next day
same can be achieved with aubergines :-)