Move the oven rack to the middle position and preheat to 250 degrees F (120 C).
Cut a large piece of foil that's about four times the width of your salmon fillet, and a few inches longer. If your foil is not long enough, you may need to join a few sheet together by lining the edges up and folding them over a few times.
Scale and debone your 680 grams salmon fillet and then use paper towels dry the surface of the fish.
Rub 2 tablespoons olive oil on both sides of the salmon and place the salmon skin-side down on the foil.
Rub in the 3 cloves garlic and sprinkle with the 1 lemon zest, 1 teaspoons ground coriander, ½ teaspoon salt and ground black pepper.
Fold the aluminum foil up and over the salmon and seal the top by folding down the top edge 3 or 4 times.
Fold the left and right sides of the foil 3 or 4 times to make a package and place the package on a baking sheet.
Bake the salmon for 25-30 min or until thermometer reads 135 F (57 C).
To make the sauce, add the 30 grams cilantro, 20 grams flat leaf parsley, ¼ cup extra virgin olive oil, 3 tablespoons lemon juice, 1 clove garlic, ½ teaspoon salt, and ¼ teaspoon ground white pepper to a small food processor or blender. Process until smooth.
Cut the 1 avocado in half lengthwise, and then remove the pit, and peel. Cut the avocado into ½" cubes and then toss with a little lemon juice to keep it from oxidizing.
To serve the salmon, you can unwrap it and cut it up into portions or transfer it whole onto a serving platter. Drizzle some sauce on and around the salmon and scatter the avocado on top.