Heat the oven to 400° F and line a sheet pan with parchment paper or foil.

Season the salmon with salt and pepper.

In a pie plate or shallow bowl, whisk together the miso paste, maple syrup, rice wine vinegar, soy sauce, garlic and ginger.  Place the salmon fillets in the marinade and turn to coat evenly.  Allow the salmon to sit in the marinade for 10 minutes or so.  The longer it marinades, the more flavor it imparts onto the salmon.

Place the salmon fillets onto the sheet pan, skin side down.  Add the broccolini to the pan and drizzle the broccolini with sesame oil, then season with salt and pepper and a pinch of red pepper flakes.

Bake until the salmon is cooked through and opaque about 12 - 15 minutes.