Rotisserie Chicken Panini with Roasted Sweet Red Pepper, Spinach, and Guacamole

Ingredients

• 1 (6 inch) submarine sandwich roll, sliced lengthwise
• 1 slice Pepper Jack cheese
• 3/4 cup cooked rotisserie chicken meat, shredded or sliced, or more to taste
• 1 medium roasted red pepper
• 1 thin slice red onion, separated into rings
• 2 slices cooked crispy bacon
• 1/4 cup fresh spinach leaves, or to taste
• 1/3 cup prepared guacamole
• 1 teaspoon unsalted butter
• 1 spear dill pickle