You wanna make the sauce yourself or use a jar?
EDIT: I buy the jars of white sauce.
Get 2 onions, 1 clove garlic, 1.5lbs of mince, 2/3 tins of chopped tomatoes, pasta sheets, white sauce and red cheddar cheese. (Dried spices like oregano or mixed italian go well)
Chop and fry onions in large pot on medium heat in olive oil, add garlic, when the onions are see through add your tins of tomatoes and spices (and red wine if you have any). Let it simmer gently water evaporating. When its nearly think enough to be sauce like fry mince in frying pan till grey and throw into sauce. Let simmer for about 5-10 mins so the mince and sauce mix (add water if sauce gets too thick).
Now take off heat and if you want leave sit to cool down (its nicer when it's "set").
Put a layer of pasta sheets in a lasagne dish, cover with white sauce then grate a small bit of cheese. Add a layer of mince/sauce. Make another pasta layer with cheese and white sauce, then mince layer. So on until the dish has about 1/2 inch left. Put final pasta layer on top with white sauce and lots of cheese. Cook at 200C for 15mins or until cheese on top is cooked.
Whip it out, eat what you want and freeze the rest in Tupperware container then microwave when needed.
You can use beer as a basis for your sauce aswell, just takes longer to evaporate the liquid off the sauce. You cook it once and get multiple servings, so although it takes a while to make initially, you can have 3-4 servings ready that take only 4-5mins to microwave from frozen.
Enjoy!