Beef Noodle Casserole

1 large onion, chopped

1 medium green pepper, chopped

1 (14 3/4 ounce) can cream-style corn

1 (10 3/4 ounce) can condensed tomato soup, undiluted

1 (8 ounce) can tomato sauce

1 (2 ounce) jar sliced pimentos, drained

2 tablespoons chopped jalapeno pepper

1 1/2 teaspoons salt

1/2 teaspoon chili powder

1/4 teaspoon dry mustard

1/4 teaspoon pepper

1 (8 ounce) package medium egg noodles, cooked and drained

1 (4 1/2 ounce) jar sliced mushrooms, drained

1 1/2 cups shredded Cheddar cheese