To Prepare Sauce: In A Large Skillet, Melt The Butter; Slowly Brown The Meat, Add Onion. Stir In Spaghetti Sauce And Oregano; Simmer For 35 To 40 Minutes At A Low Temperature. To Prepare Lasagna: Cook Noddles According To Package Directions. Drain Well. Handle Noodles Carefully To Keep From Tearing. Place A Layer Of Noodles In The Bottom Of A Buttered Baking Dish. Top With A Layer Of Sauce. Sprinkle 1/3 Each Of The Cheeses. Repeat The Proceedure Two More Times. Reserve A Small Amount Of Sauce For Top Layer To Make A Colorful Dish. Sprinkle Top With Paprika.