Preheat oven to 450 degrees F.
In a large cast iron skillet, add potatoes, olive oil and half of the dill
Season with salt and pepper
Roast 15-20 minutes, or until potatoes are almost tender.
Blot halibut filets with a paper towel to remove any moisture and cover with lemon juice.
Allow halibut to soak in lemon juice while potatoes are cooking.
Remove pan from the oven and top with halibut filets, olives and stir in garlic.
Drizzle halibut with a little olive oil and top with remaining dill, lemon zest, and lemon juice.
Bake for 10 minutes, or until fish flakes with a fork.
Serve immediately. Garnish with extra dill, if desired.