Toss crushed crackers with melted butter and bake separately for 5 minutes before adding to the casserole top for extra crispness that won't get soggy from the creamy filling.

Temper the sour cream by whisking it with a few tablespoons of the warm evaporated milk mixture before folding into the casserole to prevent curdling and ensure a silky, smooth sauce.

Use block cheddar cheese that you shred yourself instead of pre-shredded; it melts more evenly without anti-caking agents and creates a creamier, more luxurious texture.

Create distinct layers by spreading half the rice-chicken mixture first, then half the cream sauce, repeating with remaining ingredients for even distribution and better flavor in every bite.

Reserve half your scallions to scatter over the casserole immediately after baking rather than mixing all in; this preserves their bright, fresh onion flavor against the rich, creamy dish.