1. Remove Alaska Sockeye salmon from refrigerator 15 min. before cooking. Heat grill to 375°F.
2. Place butter chunks in a food processor; process until smooth. Add mustard, orange juice, zest, ginger and salt; process until emulsified, scraping down the sides of the work bowl often. Add the green onion and pulse until mixed. Keep refrigerated, tightly covered, for up to 7 days.
3. Cut 2 pieces of wide, heavy-duty aluminum foil about 6-in. longer than the salmon side. Stack the foil pieces (shiny side down) on a baking sheet and spray generously with cooking spray. Place the salmon, skin side down, in the middle of the foil. Fold the foil sides and ends up (1 to 2-in.) to make a shallow pan around the salmon, leaving at least a 1-inch margin around the fish. Season salmon with salt and pepper.
4. Carefully transfer the foil pan to the center of the preheated grill. Do not cover the salmon with foil or close the foil over the salmon. Close grill cover and cook for 10 to 13 min., cooking just until fish is lightly translucent in the center - it will finish cooking from retained heat. Remove from the grill and let rest a few minutes before serving.
5. To serve, top each salmon portion with a dollop of compound butter.
Cook's Tip: Compound butter can be rolled into logs in plastic wrap and kept in the freezer for up to 4 months. Just slice off a few pieces for a salmon topping anytime.
Variation: Salmon can also be roasted in an oven preheated to 375°F or pan-seared and finished in the oven. Cook just until lightly translucent in the center; be sure to let the salmon rest a few minutes before serving.