Fry the mushrooms with the butter, parsley and a pinch of salt and pepper until all the liquid they give off has fully evaporated from the pan. Set aside to cool.
Take a Braai grid and unroll one sheet of puff pastry directly onto it.
Leaving a 2cm border around the edges of the pastry, spread over the onion marmalade.
Top with the steak, mushrooms, a pinch of salt and pepper and finish with the second sheet of puff pastry.
Pinch and fold over all of the edges to seal the braai pie.
Brush with melted butter, close the grid and place onto the braai. Turn it every 3 minutes for approximately 15-20 minutes or until the pie is browned and the pastry is cooked through.