This is very simple to make. You can make it ahead of time and stick it in the fridge for later (cooks for an hour). I don't know if it can be frozen or not, but I don't see why not - as long as you leave the potato chips off!
What you need:
500g ground beef
1/2 package of cooked spaghetti
2-3 carrots
1-2 onions, depending on size
1 can of mushrooms (feel free to use fresh)
2 cans of diced tomatoes
1 handful of broken potato chips (I'm sure you can find a use for the rest of the bag :-) )
salt and pepper to taste
Cook the spaghetti according to the directions on the package (or however you normally make it)
While the spaghetti is cooking, put the beef in a pan to brown.
Dice the carrots and onion and add in to the meat. Cook until the beef is mostly done and then add the mushrooms and cans of tomato. (about 20 minutes total)
Drain the pasta and then add in the cooked meat mixture. Mix well and then put in a casserole dish. Add the crumbled chips on top and cover with aluminium foil. Put in the oven for 1 hour at 160 C (325 F)
Enjoy!