Prep Time 10 minutes mins
Cook Time 20 minutes mins
Total Time 30 minutes mins
Tips for success: Always soften cream cheese to room temperature to avoid lumps. Use full-fat sour cream — low-fat breaks when baked. Let the casserole rest the full 5 minutes after baking so the sauce sets. For make-ahead, assemble without the onion topping and refrigerate up to 2 days; add onions just before baking.