6 Tbsp. mayonnaise
3 Tbsp. grated Parmesan cheese
2 tsp. lemon juice
1 tsp. prepared pesto
1/2 tsp. grated lemon zest
1/8 tsp. pepper
8 slices sourdough bread
1 lb. sliced rotisserie chicken
8 slices fully cooked bacon
4 slices smoked provolone cheese
4 slices red onion, separated into rings
8 slices tomato
4 Tbsp. butter, melted
In a small bowl, combine the first six ingredients; spread half over four bread slices. Layer with chicken, bacon, provolone cheese, onion and tomato. Spread remaining mayonnaise mixture over remaining bread slices; place over top. Brush outsides of sandwiches with butter.
Cook on a panini maker or indoor grill until bread is browned and cheese is melted, 3-4 minutes.