- Preheat Panini grill on high. Reduce heat to moderate and spray with cooking spray.
- Spread butter on 1 side of 8 bread slices and turn slices over. Spread inside of bread slices with mustard/mayo mixture.
- Top 4 slices of bread with the chicken strips, dividing equally. Place cheese over the poultry, then top with remaining bread slices, buttered side out.
- Cook sandwiches until bread is golden and crisp, 4 to 6 minutes. Cut into halves to serve.
Note: Waffle maker, griddle or skillet may also be used.