Oil in saucepan. Stir in 1 diced onion, garlic (I go overboard with the garlic, I love it! lol) 2 grated carrots, 2 grated zucchinis. When soft, add 500g mince. Brown. When cooked add either tin of diced tomatoes or 4 fresh tomatoes which are peels and chopped (you can search google for how to peel tomatoes). I add seeds as well with my fresh tomatoes.
I will then add... a bunch of random things. Sometimes some stock powder, sometimes semi-dried tomato pesto, sometimes some balsamic, sometimes tomato paste. I just taste it and add whatever I think will make it awesome. I sometimes add red wine (if I have it) or some sugar to cut through the acidity of the tomatoes (just a little bit).
Always add plenty of herbs - basil and oregano in particular.
Other additions I make occasionally are bacon and mushrooms (my partner loathes mushrooms so I chop them really finely and don't mention them...lol).
So simmer that.
Meanwhile, white sauce is flour and butter, then lots of milk. Stir stir stir. Adding milk slowly, allowing to thicken, then adding more. Eventually adding some nutmeg and parmesan cheese.
Then I pop in some mince, lasagne sheets (I prefer dried, personally), white sauce... then repeat until the last year is mince, lasagne sheet, white sauce, grated cheese (mixture of tasty, mozarella and parmesan).