Bring a large pot of salted water to a boil. Add the vegetable oil (the oil will help prevent the lasagna noodles from sticking together.)
Cook the lasagna until almost al dente, about 7-9 minutes.
Drain, then rinse the noodles under cold water to stop the cooking and help remove any excess starch.
Cover lightly with a damp towel to prevent the pasta from drying out. Set aside.
Remove sausages from casing and fry in a medium saucepan. Set aside.
Beat eggs with a pinch of salt in a mixing bowl. Add the ricotta and stir until thoroughly blended. Set aside.
Preheat oven to 375 degrees F.
Assembly:
Spoon meat sauce to cover bottom of baking dish.
Arrange lasagna noodles atop the sauce, overlapping slightly and covering the bottom of the dish completely.
Spread ricotta mixture evenly over noodles.
Sprinkle a layer of mozzarella cheese.
Sprinkle a layer of parmesan cheese.
Sprinkle some crumbled sausage.
Spoon meat sauce to cover.
Arrange another layer of noodles, and repeat steps.
On top, you should have a layer of noodles. Spoon a thin layer of meat sauce
over the noodles. Sprinkle with remaining mozzarella and / or parmesan cheese.*
Line a large baking sheet with foil. Place the baking dish on the baking sheet.
Bake until the lasagna is heated through and the top is bubbling, about 45 minutes.
*The lasagna can be made up to this point 1 day ahead. Cover tightly with plastic wrap and refrigerate. Uncover before baking. Bring to room temperature.
