Tender grilled chicken, crisp bacon, caramelized onions, and cheese all tucked between two slices of sourdough bread. It doesn't get more delicious than this for lunch!
Lightly grease inside of a panini press or pan with 2 teaspoons olive oil. Preheat panini press or pan while you assemble your sandwich. Use pastry brush to apply olive oil onto one side of both slices of bread. Onto the dry side of one slice, layer chicken, onions, bacon, spinach, and cheese. Top with remaining slice of bread, coated side up.
Place sandwich into panini press and close lid (or weigh it down in a pan). Grill for 2-3 minutes or until sandwich has compressed, bread is grilled, and cheese has melted.