Beef and Sweet Onion Sandwiches - Better Homes & Gardens Cookbook

1 - 1 1/2 pounds beef sirloin steak or top round steak, cut 1 inch thick
1/2 teaspoon coarsely ground black pepper
1 tablespoon cooking oil
1/2 of a large sweet onion, such as Vidalia or Walla Walla, sliced (about 1 1/2 cups)
3 tablespoons Dijon-style mustard
1 (16oz) loaf Italian flatbread (focaccia) or twelve 1-inch slices sourdough or marbled rye bread (I used sour dough)
2 cups fresh spinach leaves or fresh basil leaves
1 cup roasted red sweet peppers, drained and cut into 1/2 inch strips (about 1/2 of a 12 oz jar)

Trim fat from steak. Use your fingers to press black pepper onto both sides of steak. In a large skillet cook steak in hot oil over medium heat for 15-20 minutes or until desired doneness, turning once. Remove from skillet; keep warm.

Add onion to drippings in skillet. (Add more oil, if necessary.) Cook for 5-10 minutes or until onion is nearly tender, stirring occasionally. Stir in mustard; remove from heat.

Meanwhile, if using Italian flatbread, cut it into six wedges; split each wedge in half horizontally. If using sourdough slices, toast them, if desired. To serve, cut steak into bite-size strips. Top bottom halves of Italian flatbread wedges or six slices of bread with spinach, steak strips, roasted pepper strips, onion mixture, and remaining bread wedges or slices.

Makes 6 sandwiches.