In a small pot of boiling water add peas and cook until tender about 10 minutes, and drain.
Cook sausage in a small frying pan adding a 3 tablespoons of water, cook until slightly golden, and water has evaporated (watch that it doesn't burn).
In a medium frying pan add 2 tablespoons of olive oil, add mushrooms, oregano, parsley , salt and 1/4 cup of water, cook on medium heat until tender and water has evaporated, stirring occasionally , watch that they don't burn. Then add the drained peas, Italian sausage (break into smaller bits if too large) and combine well.
FOR THE WHITE SAUCE
In a medium large pot melt butter over low heat, then blend in the flour and salt, gradually stir in milk , cook and stir constantly over medium heat until mixture begins to bubble and thicken, remove from heat.
PUTTING IT TOGETHER
In a medium baking pan (I used a 12x10 inch / 30 x 25cm) spread a ladle (using a 1/2 cup ladle) of sauce on the bottom of the pan (keeps the noodles from sticking) then doing 3-4 layers , place lasagna noodles (or strips) on top (I used 4 for every level, 1 noodle break in half length wise to fit the pan if need be), add 1 1/2 to 2 ladles of white sauce (spread so that it covers the noodles), 1/4 of the mixture spread on top, 1/4 of the chopped mozzarella, and a 1/4 of the grated parmesan cheese for 3-4 layers.
Bake in 350° degree oven for approximately 20-25 minutes, broil for approximately 3 minutes until top is browned. Let sit for 5 minutes before cutting . Enjoy!
**You could always make this into a vegetable lasagna, increase the peas and mushrooms and leave out the Italian sausage.
Depending on your choice of lasagna noodles, some may need to be cooked (boiled) or use oven ready which need no pre-cooking.