Preheat a skillet over medium heat.
In a small bowl, mix the mozzarella cheese, pepper jack cheese, jalapeños, tomatoes, garlic powder, onion powder, smoked paprika, salt, and pepper until well combined.
Spread butter on one side of each slice of sourdough bread.
Place one slice of bread, butter side down, in the skillet.
Spoon the cheese mixture onto the bread in the skillet, spreading it evenly.
Top with the second slice of bread, butter side up.
Cook for about 3-4 minutes, or until the bottom slice is golden brown.
Carefully flip the sandwich and cook for another 3-4 minutes, until the other side is golden and the cheese is melted.
Remove from the skillet and let it cool for a minute before slicing in half.