For classic lasagna you should cook bechamel sauce
Chopped onion fry until golden brown colour.
Mix minced pork and beef and add to the onion.
Fry all together until meat done.
Season with salt and pepper.
When beef is ready, add chopped tomatoes skinless, or tomato sauce.
Continue cooking on low heat for approximately 10 minutes, to evaporate excess liquid.
Add greens in the end.
High, rectangular baking form grease with oil.
Put 1st lasagna sheet on the bottom.
Spread a bit of béchamel sauce
Put slice of minced meat on béchamel
and sheet of lasagna again.
Alternate layers until you reach the desired height.
The last layer should be béchamel
Sprinkle lasagna with grated parmesan cheese.
Preheat oven to 190c and bake 30 min.
You can cover lasagna with foil (after 20 min) to avoid burning the cheese.
When lasagna is ready leave aside for 10 min and serve.