Mom didn't like ricotta cheese in her lasagna (& DEFINITELY didn't like the popular substitute, cottage cheese). So she played around with the ingredients to suit herself, which included pairing mozzarella cheese with swiss cheese. Different, but deliciously so.
This recipe can be made "saucier" by not cooking down the tomato sauce as much as listed. This is totally a personal decision. Just remember that it will cook down a little more in the oven as it bakes, so adjust the sauce cooking time accordingly.
Put on a pot of water to boil for the lasagna noodles. It's OK if they get done before the sauce since the whole dish will heat up in the oven.
Brown the ground chuck, onion, garlic and green pepper together. (If you're using fresh mushrooms, add them now, instead of Step #9.) Drain well.
Add oregano, garlic salt, salt and tomato sauce to the browned meat mixture. (Add the canned mushroom LIQUID now, if used. Save the canned mushrooms until step #9.) Cook over low-medium heat until thickened, stirring often, about 30-40 minutes. (If you like your lasagna "saucier," cook only about 20 minutes.)
While cooking the sauce, cook the lasagna noodles, with the oil, in the boiling water until almost tender. Drain the noodles.
Mix the cheeses together in a bowl.
Preheat the oven to 350 degrees F. Grease (or mist with cooking spray) a 13 x 9 baking dish.
When everything is done, layer the ingredients as follows:
a little meat sauce...
...meat sauce... (Add some canned mushrooms with this layer, if you're using them.)
...1/3 of the mozzarella & swiss cheeses...
...more meat sauce.
Add a second layer of pasta, more meat sauce, more canned mushrooms (if using), cheeses, and another layer of meat sauce.
Final layer is pasta, rest of the meat sauce, last of the canned mushrooms, and finally, the rest of the cheeses.
Bake at 350 degrees F until the cheese melts & browns just a little, about 25 minutes. Watch closely to avoid overbaking.