Write an article based on this "Simmer the mixture for 30 minutes, or until it starts to thicken. Refrigerate the dish for several hours before making the potatoes."
Leave the heat on medium-high and set a timer for 30 minutes. Check and stir the skillet every 5 minutes to prevent the bottom from burning. If after 30 minutes the mixture is still not a gravy-like consistency, cook it for an additional 5 to 10 minutes. If you're having problems with your mixture thickening, try mixing 1 tablespoon (15mL) of cold water with 1 tablespoon (9 grams) of cornstarch in a small bowl. Then add that to the skillet and mix it until the liquid thickens. If you don't chill the pie interior, the mashed potatoes will sink down to the bottom of the mixture and change the consistency of the dish. So put it in the fridge for at least 3 hours, though if you could leave it overnight that would give the best results. If you're really crammed for time, pop the baking dish into the freezer for 1 hour before moving on with the rest of the recipe.