Cook lasagna noodles according to package directions, drain and rinse in cold water; set aside.
Cook spinach according to package directions, drain (very well, so dish doesn't get watery); set aside.
To prepare the sauce, combine the milk, corn starch and onion and cook and stir until it bubbles and becomes thick.
Spread 2 tablespoons of the sauce on the bottom of a 2 quart oval baking dish (or similar size). Stir the ham and seasonings into the remaining sauce.
Place 3 lasagna noodles in baking dish and spread with 1/3 of the sauce mixture. Layer spinach on top. Layer another 1/3 of the sauce, the ricotta cheese and 1/2 of the mozzarella. Layer the remaining 3 noodles on top, then the remaining sauce and mozzarella.
Bake at 375 for 30-35 minutes. Let stand 5-10 minutes before cutting.