Heat 1 tablespoon of the oil in a large, heavy bottomed skillet over medium-high heat. Add the ham and cook until it is golden but not too crisp, a minute or two. Remove from the pan and reserve. Add the remaining tablespoon of the oil, the garlic, and the mushrooms to the pan and cook, stirring and shaking the pan, until the mushrooms are golden, about 5 minutes.
Add the chicken stock and the sherry to the pan, shake it well so that all the ingredients are combined, and continue cooking the mushrooms until they are tender through, about 5 minutes.
Mince the parsley.
Add the croutons, the parsley, and the ham to the pan and cook, shaking the pan, until all the ingredients are thoroughly combined and the mushrooms are slightly crisp at the edges. Taste for seasoning and serve.