Pre-heat oven to 400 degrees
Pat down the steaks to dry. This makes a great sear when you cook.
Now take half of the garlic clove (slightly crushed) and rub the garlic on the steak.
Put lots of salt and pepper (approximately 1 tsp) on both sides. More is better because it adds lots of flavor.
Put the whole mushrooms, 3 garlic cloves, sage, and the shallot into a food processor. Blend until it looks like beautiful small chunky-rocky sand. Set aside the mixture
Now put the steaks in a medium high pan with three tablespoons of oil. Don’t touch or move the steaks. Sear 2 minutes per side. Then set aside to cool.
Place the blended mushroom mixture in a pan with 2 tablespoons olive oil and the 4 tbsp butter. Add big pinch of salt and pepper.
Cook for approximately 3-4 minutes stirring occasionally to get moister out and to get a dark brownish. Set aside to cool.
Roll out puff pastry on floured board until it has increased an extra 2-3 inches. Then using a sharp knife cut into four pieces.
Now place a teaspoon of mustard and brush on the pastry leaving inch frame on edges. Add 1/2 the mushroom mixture to center on square of pastry.
Brush a tablespoon of Dijon mustard all over each of the steaks.
Next place steak on top mushroom mound and place a tablespoon more of mushroom mixture on top of each steak.
Brush all edges of puff pastry with egg and fold up to wrap and pinch to seal in the pastry over the steak.
Place wrapped side (seamed side down) on non-stick foil wrapped baking sheet.
Using a knife poke a couple of holes on top so steam can escape.
Egg wash the top of pastry and sprinkle salt.
Bake for 20 to 25 minutes on the bottom rack
Plate and enjoy!