Dutch Potato Filling

Begin by submerging the potato cubes in a large pot and immersing them with salted water; Heat the mixture to its boiling point over high heat. Gradually decrease the heat to a lower setting, cover the pot, and let it simmer until the potatoes reach tender consistency, approximately 25 minutes. Remove from heat; allow excess moisture to evaporate for a short period of time, around 1 to 2 minutes.

Next, melt half a cup of butter in a large skillet over medium heat. Introduce the sliced onions and celery into the skillet, stirring constantly until they have reduced in size and developed a brown color, roughly 30 minutes.

Preheat your oven to the temperature of 350 degrees Fahrenheit (175 degrees Celsius). Grease two 9x13-inch glass baking dishes with a sufficient amount of cooking spray.

Combine half a cup of butter and the cooked potatoes in the bowl of a stand mixer fitted with the paddle attachment; initiate the mixing process on Low setting. Gradually add 4 torn slices of bread, 1 cup of milk, and 1 tablespoon of seasoned salt until the mixture is well combined; continue adding 4 more torn slices of bread and the remaining half a cup of milk until fully incorporated, then add 2 more torn slices of bread and allow the mixer to continue running until a desired consistency is achieved.

Introduce the onion-celery mixture, 4 more torn slices of bread, half a cup more butter, and an additional 1 tablespoon of seasoned salt into the mixer bowl until everything is fully incorporated; finally, add 2 to 4 more torn slices of bread and allow the mixer to continue running until the desired consistency is reached.

Cut the remaining half a cup of butter into thin slices. Divide the dressing evenly between the prepared baking dishes; top each dish with a slice of butter and an additional 1 tablespoon of seasoned salt. Cover the dishes with aluminum foil.

Place the baking dishes in the preheated oven and bake until the dressing has developed a brown color, approximately 1 hour.