You’ll love this easy to make steak rub that features cocoa, coffee, cumin and paprika.
In a medium bowl, mix together the mascarpone, horseradish, ketchup and 1/2 teaspoon salt with a rubber spatula. Cover and refrigerate until ready to use.
Allow the flank steak to come to room temperature for 30 minutes before grilling. Preheat a grill or grill pan to medium high.
Meanwhile, mix together the cocoa powder, coffee, cumin and paprika in a small bowl. Sprinkle the steak on both sides with 1 1/2 teaspoons salt and rub with the cocoa mixture, followed by the olive oil (to help the spices stick).
Grill the steak for about 8 minutes per side, until an instant-read thermometer registers 125ºF in the thickest part. Remove from the grill and let rest for at least 10 minutes.
Meanwhile, cut the ciabatta rolls through the equator and grill, cut-side down, until golden brown and nicely marked, about 1 minute. Spread the rolls with the mascarpone mixture.
Thinly slice the steak against the grain and pile onto the rolls. Slice the sandwiches in half and serve.