Directions:

Warm oil in a large, nonstick skillet over medium-high heat. Add steak; stir-fry until meat is no longer pink. Remove steak from pan; drain. Wipe skillet dry.

Layer six bread slices with 1/4 cup mozzarella, steak and red peppers. Sprinkle with the remaining mozzarella and feta. Drizzle each with 1 teaspoon Sriracha hot chili sauce. Top with remaining bread slices. Spread outsides of sandwiches with butter.

Warm an electric griddle or the same skillet over medium heat. Toast sandwiches, covered, for 2-3 minutes or until bread is lightly golden brown. Flip sandwiches; cook, uncovered, for 2-4 minutes longer or until bread is lightly golden brown and mozzarella is melted.