4 servings
Preheat oven to 475°; Add potatoes to a large pot, cover with 2 inches of water and 2 tsp salt; boil over high and cook 10-12 min until just tender; drain and spread on a sheet pan to cool slightly; using a glass (or your hand), smash potatoes, drizzle with 2-3 tbsp oil and salt/pep; roast 10 min, flip and roast 10-15 min until golden and crispy. Meanwhile, oil a baking dish; add asparagus and top with ½ cup sauce; when 15 min remain on potatoes, bake asparagus until tender, 12-15 min. Pat 4 fillets dry and season with salt/pep; heat 2 tbsp oil in skillet over med-high (get the pan hot, otherwise fish will stick); in batches, sear fillets skin-side down 5-6 min until fish releases from pan; flip and cook 1-2 min until cooked through
Divide all between plates.