Whisk honey, soy sauce, garlic, lemon juice, olive oil and red pepper flakes in a small saucepan.

Simmer over medium heat for 4 to 5 minutes, stirring, until the glaze coats the back of a spoon and has reduced by about a third.

Line a rimmed baking sheet with foil and lay the salmon skin-side down; brush half the glaze over the top and let sit at room temperature 15 minutes, or cover and refrigerate up to 8 hours.

Preheat the oven to 400F.

Roast the salmon for 12 to 15 minutes, until it flakes easily with a fork at the thickest part.

Switch the oven to broil, brush on the remaining glaze, and broil for 2 to 3 minutes, watching closely, until the top turns deep amber and slightly sticky.

Let rest 5 minutes, then slide onto a serving platter.

Scatter with lemon slices and parsley just before bringing it to the table.