Cover potatoes with water in a medium saucepan and boil until fork-tender, 8 to 10 min.
Heat a large non-stick frying pan over medium. Add oil, then carrots, onion and green beans. Cook, stirring occasionally, until carrots are tender, 5 to 7 min.
Pat salmon dry with paper towels. Remove and discard skin from salmon, then cut salmon into bite-sized pieces. Toss salmon and scallops with flour and salt in a medium bowl. Add seafood to pan. Cook 2 min, then pour in 1⁄2 cup cream. Cook until thickened, 1 to 2 more min. Stir in lemon zest and juice. Spray an 8 x 8-in. baking dish with oil. Scrape seafood mixture into prepared dish.
Position rack in top third of oven. Preheat broiler. Drain potatoes. Mash with remaining 1⁄4 cup cream and garlic salt. Spread over fish mixture. Broil in top third of oven until lightly golden, 5 to 7 min.
Nutrition (per serving)
Watch below for instructions on how to make Crunchy bacon macaroni & cheese.