casserole dish of scalloped potatoes
The Simple Tip That Will Give Scalloped Potatoes The Best Texture
By Betsy Parks
Scalloped potatoes fresh out of the oven are difficult to cut and serve because the potatoes' starches are still hot and full of moisture. The solution is to wait for them to set.
For the best results, let your potatoes rest for 15 to 20 minutes to cool down their internal temperature and allow the creamy sauce to thicken before serving.
When potatoes cooked with water, milk, or cooking stock reach around 140–149 degrees Fahrenheit, the starch molecules swell and explode, then stick together when cooled.
Scalloped potatoes might seem like a different animal since they're baked, but they're actually slowly cooked in milk and cream, and the potato starch thickens this sauce.
When you pull the dish out of the oven, the starch molecules are dissolved in the hot cooking liquid. As the dish cools down, the starches contract and congeal into a thick sauce.
If you rest the dish for a few minutes, the potatoes will still be warm enough to serve, and the starches will congeal with the cream and cheese to create a more pleasing texture.