Preheat oven to 450 degrees. Line a baking sheet with aluminum foil (for easy clean-up) and brush with olive or canola oil. Don’t bother to brush the pan with oil if you are using skin-on filets. Set aside.
Place salmon filets, skin side down, on the prepared baking sheet. Drizzle with olive oil and season with salt and pepper. Transfer to oven and roast until done to your liking. (I like mine just cooked all the way through which will take about 10-12 minutes).
Meanwhile, make the Creamy Mustard Dill Sauce: Heat oil in small saucepan over medium heat until shimmering. Add shallot, reduce heat to medium-low and sauté until soft, 1-2 minutes.
Add white wine and simmer until reduced by half, about 2 minutes.
Add mustard, cream and water. Simmer until thickened slightly, 2-3 minutes.
Remove from heat and add fresh dill.
Arrange bread slices on your work surface. Butter the bread.
Add a handful of watercress to each slice of bread.
Remove salmon from the baking sheet, leaving the skin behind if necessary by coming between the salmon and the skin with a thin metal spatula. It should come up quite easily. Place a salmon filet on top of watercress on each slice of bread.
Artfully arrange a generous dollop of mustard sauce and a spoonful of pickled beets around or on top of the salmon. Garnish with fresh dill. Serve immediately.
Recipe inspired by a dish at Fika, the cafe at the American Swedish Institute in Minneapolis, Minnesota