Mix the rub ingredients together in a bowl. Coat the salmon with a generous amount of the rub. (Store the rest of the rub in an airtight container.)
Start on the rutabagas and leeks while the salmon rests.
In a large pot, cover the rutabagas with about one inch of cold water. Add a generous pinch of salt and boil until tender, about 30-40 minutes.
Heat 2 tbsp. of olive oil in a large pan on medium-high. Add leeks and sauté until tender and browned. Set aside.
Drain the rutabagas and return to the pot. Add salt and butter and mash. Stir in sauteed leeks.
Preheat oven to 400 degrees. Bake the salmon skin side down on a baking sheet covered with foil until medium rare. (Or barbecue on a grill over medium heat, skin side down. Note that because of the high fat content of the salmon, it may flame on a barbecue. An alternative is to use soaked cedar planks.)
Plate the salmon over the mashed rutabagas and sautéed leeks. Serve, and enjoy!