I have made a few modifications to this recipe.
First as vegetarians, salami isn’t going to work for us, but LightLife Gimme Lean sausage works just fine. I also use buttermilk in the potatoes. I never have the high-end mozzarella around, but the regular kinds work well: gruyere works well too, and I intend to try a smoked mozzarella sometime.
The full 40 minutes of baking is worth doing: you want the cheese to be molten . . . .