Prepare the salmon by patting the skin and flesh dry with a paper towel. Generously sprinkle salt and pepper on the skin side and set aside.
During the last 15 minutes of roasting time, on medium-high heat, heat the remaining 1 tbsp of butter until it turns into brown butter (take care not to burn the butter, see this visual guide here for browning butter). Add the tbsp of olive oil.
Place the salmon fillets skin side down in the non stick pan and reduce the heat to medium. Using a flat spatula, gently press down on the salmon fillets, so they maintain proper contact with the hot pan. Let them cook for 6-7 minutes, until the skin is crispy, and the salmon looks cooked half way up the sides.
Sprinkle the flesh side generously with salt and pepper, and flip it over to cook on the flesh side for another 1-2 minutes, or until your meat thermometer registers 120°F when inserted into the thickest part of the salmon.
Remove from the pan immediately, and place them on a plate, skin side up (to prevent the skin from getting soggy). Turn the heat to low and return the pan to the stove.
Remove the vegetables from the oven. Divide the roasted vegetables into two plates. Place each piece of salmon ontop of the asparagus spears. Place some of the kumquats on top of the salmon.
Transfer the juices and roasted garlic in the roasting pan, to the non stick pan on the stove. Add the chopped dill and cream and mix while crushing the garlic into the sauce.
Add a splash of wine to dilute the sauce a little (if you prefer) and drizzle over the roasted vegetables and salmon. Serve immediately.