Made a recipe from a French cookbook that was almost identical. Ingredients were the same (minus the mushrooms), but cooking technique was a little different. After frying the potatoes 10 minutes, stirring occasionally to ensure that all sides were browned, it called for adding 1 cup of water, seasoning to taste, and simmering 10-15 minutes, covered. When water was gone potatoes were re-fried slightly to give some crispness. Your recipe looks more authentic, but this version was super easy because it required almost no attention.
I made half the recipe and ended up eating all of it and none of the chop I had planned. I used duck fat instead of goose fat, as that was what I had, and it worked very well. Instead of cepes I used plain button mushrooms, which unfortunately did not add much in the way of flavor. Note that the nutrition facts did not count the fat, and these are going to have quite a bit of fat, just as home fries would. The parsley adds a nice fresh note.