Found this recipe on a Palaeo website. I was sceptical but actually it's even nicer than 'proper' lasagne...
Make up your meat sauce as usual - I fry minced beef with onions and garlic and add a jar of Zest pasta sauce (6g carb the jar).
While this is cooking peel, halve and de-seed a butternut squash and cut into thinnish slices - you need a very big, very sharp knife for this.
Layer the meat sauce and squash slices in your lasagne dish until all used up, beginning and ending with meat sauce.
Cover with foil and cook in a hot oven for 30 minutes, then remove the foil, sprinkle with strong cheddar cheese (my addition to the recipe) and return until crispy on top and bubbling, about another 15 minutes. The squash should be al dente, cooked but not soggy. Take out of the oven and let stand for ten minutes before serving. YumYum yum yum yumyumyum...