Put a medium sized saucepan over heat and add the oil then the onion. Saute the onion till it is soft. Then add the sausage mince a bit at a time, stirring occasionally until all of the sausage is added. Add the garlic and stir, cooking till the sausage is cooked through.
Add a 60 ml / 1/4 cup of water to remove some of the flavour and brown bits from the pot. Let it bubble a bit then tip the meat mixture into a bowl
Wipe down the pot. Heat again and add the butter let it melt and add the flour stirring continuously with out letting it colour. Add the chopped tomato and stir well. The sauce will thicken so begin to add the cream and the tomato passata a bit at a time. Simmer on low for 10 minutes. Season well.
Meantime put a large pot of water onto the stove and cook the sheets of lasagne. Put each one into a bowl of cold water and leave till needed.
All that is left to do is to layer it now. Put aside one to two sheets of lasagne for the topping.
First put about a cup and a half of the sauce onto the bottom of the dish. Dig the sheets out of the water and shake ( continue to do this) Put a sheet and a half of Lasagne into the dish then sprinkle on sausage and 1/3 of the ricotta and 1/3 of the mozarella. Follow this with another sheet and a 1/2 of pasta and red sauce with a sprinkling of parmesan. Follow again with layers of sausage, ricotta and cheese. Continue with the ingredients you have but save enough red sauce for the top.
Sprinkle the top with cheese then get a large spoon and make 6 whole in the top by pressing in and making a bit of a shallow whole. Cut the pasta sheets into ribbons and put a piece like a little nest around the whole to hold the egg in. . Cover the Lasagne with cling wrap and refrigerate till the next day if you like.
Take it out of the fridge up to an hour or so before you need to bake it to let it warm a little.
Cover the lasagne with foil and bake for one hour . Test the inner temperature by inserting a fork or toothpick into the centre then feeling if it is hot. Put it back in for a short time if not
Uncover the lasagne and break an egg into a cup and pour into a nest. Continue with the eggs until all the nests are full. Put back into the oven for 20 minutes or just till the eggs are set.