Generously coat with cooking spray.
Heat a cast-iron grill pan over medium-high.
Transfer to a plate; let cool.
Photo: Caitlin Bensel
Stir together mayonnaise, mustard and horseradish in a small bowl.
Using a small food processor, whirl the olives and brine into a spreadable puree.
Spread 1 1/2 teaspoons mayonnaise mixture on each of the remaining 4 bread slices.
Sprinkle evenly with remaining 1/8 teaspoon salt and remaining 1/8 teaspoon pepper and top the sandwiches.
If you like, add a little more arugula for bite.
Serve sandwiches whole or cut in half.
- Daily Values (DVs) are the recommended amounts of nutrients to consume each day.
(-) Information is not currently available for this nutrient.
