Stew Stuffed Potatoes - Crockpot recipe

Very good stick to the ribs dinner.  It is a strange combo of cooking and is a bit time consuming, but very well worth the time and effort.  To make this dish you will need:
8 cups low-sodium beef stock
4 large Idaho potatoes
Olive oil
2 pounds beef cubes (can use chuck) cut into 1-inch cubes
salt and freshly ground black pepper
Water, as needed
1 package of frozen pearl onions
1 8 ounce slice mushrooms
Pam
1 tablespoon creamy horseradish sauce
1 tablespoon butter
2 tablespoons flour
1.)  Preheat the oven to 400 degrees F.
2.)  Put the beef stock in a large pan over medium heat and bring to a boil. Cook until the liquid is reduced by half, leaving 4 cups.
3.)  Pat the meat pieces dry with paper towels and season with salt and pepper. Put the meat, onions, mushrooms and the reduced stock in a crock pot. Cook for 4 hours on high or 8 hours on low.
4.)  Put the potatoes on a rimmed baking sheet and cook until tender, about 45-60 minutes. When cool enough to handle, cut potatoes in half lengthwise and using a spoon, remove the potato flesh and reserve, leaving 1/2-inch thick rim around the edges. Spray the baking sheet with Pam and put potato shells on it, cut side down; bake until the cut side is golden brown and skin is crispy, about 20 minutes.
4.)  To the reserved potatoe flesh mash with the horseradish cream and buter until smooth. Add 1 tablespoon olive oil, season with salt and pepper, to taste, and mix well.
5.)  Remove a 1/2 cup of the stock from the crockpot, mix with the 2 tablespoons of flour until smooth.  Stir back into the crockpot to thicken the stew.
6.)  Ladle the stew into the potato bowls, top with a spoon of mashed potatoes and enjoy.