I originally got my lasagna recipe from THE JOY OF COOKING. I modified it through the years to suit our tastes. My Mom loved it, always reminding me to use lots of sauce so it wouldn't dry out. My husband is the cook now and has tweaked the recipe (he thinks I can't tell, but I can!); this is the one he has been baking and it is a family favorite.
Make your sauce. Saute onion and garlic in a bit of olive oil for a couple of minutes. Add beef and salt and pepper. When meat is fully cooked, add diced tomatoes, sauce and oregano. Taste for salt and add if needed. Cook on low to medium for at least an hour.
Spray lasagna pan, or 9x13 cake pan if that's all you have. Put some sauce on bottom, then layer as follows: noodles, provolone, ricotta by the teaspoon (drop here and there, it will melt in and mix as it bakes), mozarella and parmesan. Top with sauce and repeat layering. Top it all with final layer of sauce and a light dusting of parm.
Bake, covered, for 45 minutes at 325 degrees. Uncover and bake 10 or 15 minutes more. LET SIT for at least 10 minutes before serving so it can set up a bit.
Notes: You might have leftover sauce, you can serve on the side or save for another use. If you used a 9x13 pan, you will have leftover noodles also.