6 ounces baby bella mushrooms, very finely chopped
¼ cup finely chopped shallot
3 cloves garlic, minced
1 tablespoon finely chopped curly parsley, plus 12 small sprigs for serving
1 teaspoon dried thyme
1 teaspoon dried rosemary
1 puff pastry sheet, thawed
1 egg
1 teaspoon water
1 tablespoon mayonnaise
1 tablespoon Dijon mustard
Directions
Preheat the oven to 400 F.
Season filets with ½ teaspoon each salt and pepper on either side.
Heat the grapeseed oil in a cast iron skillet over medium heat.
Sear the seasoned steaks until dark brown on the outside and medium rare on the inside, about 3 minutes per side. The steak should be underdone.
Remove the steaks from the skillet and place onto a plate. Once cool to touch, wrap in plastic and chill in the refrigerator while preparing the duxelles.
Melt butter in a skillet over medium heat.
Add the mushrooms, shallot, and garlic and cook until mushrooms are tender and glossy, about 5 minutes, stirring constantly.
Stir in the parsley, thyme, rosemary, and ¼ teaspoon each of salt and pepper. Remove the duxelles from heat and set aside.
Remove the filets from the refrigerator and slice into 1-inch cubes.
Unroll the puff pastry onto a floured surface and slice into 1x2-inch strips.
Dollop a spoonful of mushroom duxelles onto the center of each strip.
Place a piece of steak on top of the mushrooms.
Whisk egg and water together in a small bowl.
Brush egg wash on one end of each puff pastry strip, then wrap the puff pastry around the filling to enclose, using the egg wash to seal.
Transfer the bites to a parchment-lined sheet tray and brush with egg wash.
Bake the bites until crispy, puffy, and browned, about 20 minutes.
While the bites are baking, mix the mayonnaise and mustard together in a small bowl.
To serve, dollop each bite with the mustard mixture and garnish with parsley.