Slice potatoes and Jerusalem artichokes into 1/8 inch slices
Arrange potato and Jerusalem artichoke slices in roasting pan
Place in middle rack and bake for 15 mins
Take roasting pan out from oven and place fish fillets (skin side up) and onion wedges on top
Return to oven and bake for 10 mins then boil at 500F until salmon skin is crisp
Garnish with parsley flakes and drizzle freshly squeezed lemon juice to serve
You can definitely fit more salmon fillets over the root veggies if you want to serve more! There might not be enough side dish for more servings so you might want to prepare something more on the side.