Grease a 13×9″ baking dish. Prepare rice according to package instructions.
While rice is cooking, melt 1 tablespoon butter in a medium skillet over medium heat; add onion to butter and cook until tender.
In a large bowl, mix together cream of chicken soup, sour cream, and pepper. Stir in onions and broccoli. Mix in cooked rice, adding it in several batches. When everything is combined, stir in 8 ounces of shredded cheddar cheese (about 2 cups).
Spoon evenly into greased baking dish. Melt remaining 2 tablespoons of butter. Top with remaining cheddar cheese and sprinkle evenly with crushed crackers. Drizzle top of crackers with melted butter.
Bake a 350 degree F oven for 30-40 minutes or until casserole is hot and top is golden brown.
Option: Add cooked chicken to make this a main dish entree.