Cook pasta in a large pot of salted boiling water until tender, but still firm to bite (or follow the cooking instructions on the package). When pasta is ready, drain and set it aside.
In a large bowl combine cooked pasta, mushroom sauce and 1 1/2 cups shredded cheddar cheese. Add salt and pepper to taste.
Preheat the oven to 350 degrees F. Spread a little cooking oil around the inside of a 8x11-inch baking dish, then place mixture in the baking dish and sprinkle remaining cheese all over the mixture. Place on the middle rack of the oven and bake until bubbling around the edges and golden brown on top. Serve immediately.