Place the cedar plank in water to soak, about 30 minutes.

Preheat an outdoor grill for medium-high heat and lightly oil the grate.

Stir butter, lemon juice, herbes de Provence, dill, tarragon, paprika, and garlic together in a small bowl.

Place halibut steaks on the cedar plank. Season to taste with pepper; spoon half the butter mixture onto the halibut.

Place the cedar plank into the grill; cook, with grill lid closed, for 20 minutes. Open grill; baste halibut with remaining butter mixture. Continue grilling until fish flakes easily with a fork, about 10 minutes.