In a medium sauce pot, bring Russet Potato (4) to boil in heavily salted water, along with the sachet of Bay Leaf (1), Black Peppercorns (1/2 teaspoon), and Fresh Rosemary (2 sprig).
Cook until potatoes are fork tender, about 35-40 minutes. Drain from water, once potatoes are done, and discard sachet.
In a small sauce pot, warm up together Milk (1/2 cup) and Butter (1/4 cup). Add Sour Cream (1/4 cup) and Salt and Pepper (to taste).
Using a stand mixer, fixed with the whisk attachment, beat potatoes until mealy and broken up.
Slowly add milk mixture to potatoes. Once liquid has been added, speed up mixer and beat potatoes until creamy texture is achieved.
Add Provolone Cheese (0.66 pound), Fresh Chives (0.5 ounce), and Salami (2.5 ounce) to potatoes. Mix until well incorporated.
Preheat oven to 350 degrees F (175 degrees C).
Grease a casserole dish with some of the Butter (1/4 cup) and some of the Breadcrumbs (3/4 cup). Scrape potato mixture out of mixing bowl and into breaded casserole dish. Even out the top and top with more bread crumbs and butter.
Place in preheated oven and bake for 20 minutes.
Serve alongside your favorite roast or other main dish.