Heat oven to 425 F.
Melt butter in the pan over medium-high heat in a large skillet.
Season salmon fillet with salt and pepper.
Once butter is melted in the pan, add seasoned salmon to the center of the pan. Place broccolini around the salmon. Top the salmon fillet with 2 tablespoons of dill frond.
Place skillet in the oven for about 12 minutes or until salmon is cooked to 145 F at the thickest point.
Garnish with lemon slices, remaining dill and flake salt.