Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
In a medium skillet over medium heat, melt butter with salt and cook until just brown. Remove from heat and toss with pasta, cheese and oregano. Pour into a 7x11 inch baking dish.
Bake in preheated oven 10 to 15 minutes, until hot and bubbly.