My husband and I have been having this "which way is the more authentic lasagna" argument ever since we got married. We've asked numerous resources and never gotten a satisfactory answer.
The north/south Italy idea has been brought up several times, but it still doesn't explain why all UK restaurants have the bechamal sauce and no US ones do. We've been to Italian restaurants in London, run by Italian chefs, and they make it the "English" way, and we've been to Italian restaurants in the US run by Italians and they make it the "American" way.
I learned how to make a Delia Smith lasagna for my husband very early on (without the chicken gizzards however!
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) and I will make that for him from time to time. The no-cook lasagna noodles work for the English way - just don't overlap them.
I've never stopped preferring the American way though. I love tomato sauce with wine, garlic, onions, loads of basil. Like Bmore2Uk's friend, I put some Italian sausage meat in with the ground beef too. Yummmm...