Preheat oven to 500 degrees and place an aluminum lined baking sheet in the oven. Pat salmon dry with paper towels, season with kosher salt and freshly ground black pepper.

Meanwhile, melt butter in a skillet over medium heat. Add panko and season with salt and pepper. Stir frequently until panko is golden brown. Transfer to a bowl and let cool completely, then stir in thyme thoroughly.

In a separate small bowl, combine tarragon, mustard and mayonnaise.

Using a spoon, spread tarragon mixture evenly over each fillet. Sprinkle panko mixture evenly on top, pressing with your fingers to adhere.

Once oven reaches 500 degrees, remove rimmed baking sheet from oven, lower oven temperature to 325 degrees, and drizzle olive oil over baking sheet. Carefully place salmon onto it, skin-side down. Roast until the thickest part of the fillet registers to 125-degrees on an instant-read thermometer, about 10-13 minutes.