This is optional, but to help with clean-up you can line a large sheet pan with aluminium foil. If you don’t, you’ll just have to scrub the pan a little more.
Preheat your oven to 430°F (or 390°F if you’re using a convection oven).
Place the potatoes on your sheet pan and toss them with 1 tablespoon olive oil and 1/2 teaspoon salt. Bake for 10 minutes.
Remove the pan from the oven and add the green beans, tossing them with an additional 1/2 tablespoon of olive oil. Return to the oven and bake for another 10 minutes.
While the vegetables are baking, whip the butter in a small bowl using a fork. Stir in the breadcrumbs, minced garlic, herb mix and salt. Spread this evenly over the four salmon fillets.
Remove the pan from the oven once more and make room for the fish. Add the four salmon fillets and bake for another 10-15 minutes, or until the fish is cooked and flaky all the way through.