Mexican Torta Sandwich

Name: Mexican Torta Sandwich
Cuisine: Mexican, Latin American, American
Ingredients: 4 bolillo or telera rolls, sliced in half lengthwise; 500g cooked chicken, beef, or pork (shredded or sliced); 4 slices of ham (optional); 4 slices of panela or Oaxacan cheese; 1 avocado, sliced; 1 cup refried beans; 1/4 cup pickled jalapeños; 1/2 cup shredded lettuce; 1 tomato, sliced; 1/2 onion, thinly sliced; 1/4 cup mayonnaise; 1/4 cup Mexican crema or sour cream; 2 tbsp butter; Salt and pepper, to taste