Preheat oven to 450°; mix potatoes with 1 tbsp oil, salt/pep + fave spices; roast on sheet pan 15-18 min until tender

Meanwhile, pat fish dry + season with salt/pep; heat 1 tbsp oil in skillet over med-high (get that pan hot, otherwise the fish will stick) + sear fish 3 min; flip + sear another 1-2 min (for well done cook 3 min on second side); set aside, reserving pan juices

Drain 2 tbsp capers (rinse if desired); add capers, lemon juice + butter to halibut pan; sauté 2-3 min scraping up brown bits until butter melts

Divide halibut + potatoes to plate; top halibut with caper butter sauce