Add 2 tablespoons of the butter to an extra large pan or cookware.  Add the onions and cook on low-medium heat for about 4 minutes.

Raise the heat to medium and add the mushrooms along with another tablespoon of butter.  Season with the salt and cook for 6 to 7 minutes.  The salt will help draw out the moisture from the mushroom.  We want to get most of the moisture out of the mushrooms before adding the rest of the ingredients.

Add the ground beef to the pan.  Sprinkle in the onion powder, celery salt, garlic powder, black pepper, and chicken bouillon cube.  While stirring, cook until no longer pink.  This will take about 4 to 5 minutes.  For best flavor, do not drain the fat.  This will be absorbed by the potatoes and add a lot of flavor to your dish.

Stir the flour in to the ground beef and cook for an additional minute or two.  We are using this to thicken the sauce.

Pour in the chicken stock, ketchup, and 1/2 cup of the heavy cream.  Lower the heat back to low-medium.  Cook for 15 minutes while occasionally stirring with a wooden spoon.

The meat sauce can be made ahead of time and refrigerated overnight.  On the day you plan to assemble and bake the dish, take the meat sauce out of the refrigerator 30 minutes before you plan to use it.

Peel and slice the potatoes into approximately 1/3 inch thickness.  No need to be precise since we are going to para-boil the potatoes ahead of using them in the dish.

Add the sliced potatoes to a pot of water.  Bring the pot of water to boil.  Cook until you can just start to be able to insert a knife into a slice of potato.  You don't want to over cook them since they are going to bake in the oven.  Drain and set aside.

Butter a 9 by 13 inch baking dish.  Layer half of the potatoes in the dish.

Top the potatoes with half of the ground beef mixture, followed by half of the cheeses.

Layer the second half of the potatoes.

Follow that by the rest of the ground beef and reminder of the cheeses.