i want to make a tuna and sweetcorn thingy - like a cottage pie - but not sure how to go about it

[Tutter]

i.e. what should go with the tuna and sweetcorn, under the mash -- a cheesey sauce? the simpler the better please!

I would think a cheese sauce, or just a white one would be nice - or maybe fish stock (have you got any fish stock cubes?)
I have to admit I'm basing this on my memory of DS cooking a tuna & sweetcorn sauce to go with spaghetti - I don't cook fish as I'm allergic to it.

yep - a cheese sauce. I would also add onion, and maybe pepper and/or mushrooms as well. Saute the onion and other veg before you mix it with tuna and sweetcorn and cheese sauce though.

yes, agree onion would be good

ok, so i fry onion, take out and whizz up (ds awful fussy about lumpy onion)

then make cheese sauce, chuck in tuna, sweetcorn and blitzed onion

mash on top

sound ok?

Yep, sounds fine to me