Ingredients

• 1 cup crumbled Stilton cheese
• 2 tablespoons mayonnaise
• 1 tablespoon prepared horseradish
• 8 3x5-inch sourdough bread slices
• 1 pound thinly sliced roast beef
• 1/2 red onion, thinly sliced
• 1 bunch arugula, stems trimmed
• 2 tablespoons (1/4 stick) butter

Instructions

1. Mash first 3 ingredients in small bowl until almost smooth. Place bread on work surface and spread mixture on 1 side of each slice. Top each of 4 bread slices with 1/4 of beef, then onion and arugula. Season with pepper. Top with remaining bread, cheese side down.
2. Melt butter in heavy large skillet over medium-high heat. Add sandwiches and cook until golden, about 2 minutes per side. Serve hot.