Preheat the oven to 375°F.
In a small saucepan, melt 1 tablespoon of the butter over medium heat. Add chopped shallots and sauté for 1 minute, stirring occasionally.
Add the vinegar and white wine. Simmer until the liquid has nearly evaporated.
Stir in the heavy cream and a pinch of kosher salt. Bring to a low boil.
Reduce heat to low and add the remaining butter, one piece at a time, whisking constantly until fully emulsified. Set sauce aside, keeping warm.
Meanwhile, pat the salmon fillets dry with paper towels and season with kosher salt.
Place the salmon on a baking sheet and bake for 11 minutes. Turn on the broiler and cook for an additional 3–4 minutes until just cooked through and slightly golden on top.
Plate the salmon and spoon the beurre blanc generously over the top. Garnish with chopped dill and serve immediately.