In a large bowl, combine steak pieces, potatoes, melted butter, garlic, herbs de Provence, salt, and pepper. Toss to coat evenly.
Divide the mixture into four equal portions and place each portion in the center of a sheet of aluminum foil. Fold the edges of the foil to create a secure packet.
Place foil packets on a baking sheet and bake in the preheated oven for 25 minutes or until steak is cooked to desired doneness and potatoes are tender.
Carefully open the foil packets and garnish with fresh parsley before serving.
Notes
For extra flavor, you can add a splash of lemon juice before sealing the foil packets.