Bring the salmon to room temperature (leave out for 30 minutes ahead).
Melt the butter, honey, brown sugar, lemon juice and fish sauce in a small pan over low heat. Stir to incorporate all the ingredients. Keep warm on a low simmer. The sauce will thicken to a syrupy consistency.
Lightly coat salmon with oil. Season with salt and fresh ground pepper.
Heat a non-stick or cast-iron pan over medium heat.
Place the salmon skin side down and sear for 4-5 minutes. Shake pan occasionally to ensure it is not sticking. Flip the salmon and sear for another 3-4 minutes. Use your tongs, pushing down on the fish, to ensure the thinner sections are searing.
Reduce the heat to low. Flip back to the skin side down. Pour the sauce over the salmon. Cook for another 4-5 minutes. Use a dinner spoon to baste the salmon with the sauce the entire time. Be sure to get the glaze on the side, as well.
You should reach a temperature of 125 to 135 degrees, depending on how well-done you like your salmon.
Time may vary depending on the size and thickness of your filet. Make sure you get crispy skin and a golden sear on the top. Time for less or further cooking can be done while basting to ensure you get the doneness you prefer.