Grind porcini mushrooms to a powder in a coffee grinder or a blender. Transfer to a bowl and add all other ingredients. Stir until fully combined and mixture is a paste.
Brush the steaks on both sides with the porcini paste. Cover and refrigerate for at least 30 minutes.
Prepare a medium-hot fire in your grill. Grill the steaks, covered, for 3 to 4 minutes on each side for medium-rare.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy Karen Adler and Judith Fertig, adapted from BBQ Queens Big Book of Barbecue, published by Harvard Common Press, 2005