Prepare a small baking dish (11x7 rectangle, 8x8 square or 1.5 to 2 Qt Oval) by greasing it with butter and sprinkling the bottom with a light coating of parmesan cheese.
In a medium bowl, gently mix together the rice, sour cream, scallions, chiles, shredded cheese, salt and cayenne.
Spread the mixture in the dish and smooth the top. Sprinkle with more parmesan cheese and dot with butter.
Bake for 20 minutes, until the top and edges start to show a little light brown.