Savory Ham and Cheddar Panini

• 1/4 cup
  Mayonnaise creamy or Greek yogurt
• 1 tbsp
  Dijon mustard smooth or Whole grain mustard
• 1/4 tsp
  Cayenne pepper ground or Paprika
• 1/4 tsp
  Black pepper freshly ground or White pepper
• 1 whole
  Red onion thinly sliced or Yellow onion
• 8 slice
  Ham smoked or Turkey
• 4 slice
  Cheddar cheese sharp or Swiss cheese
• 8 slice
  Bread sourdough or Whole grain bread
• 2 tbsp
  Butter unsalted or Olive oil

Instructions