In a mixing bowl, combine the softened cream cheese, shredded cheddar cheese, diced jalapeños, mayonnaise, garlic powder, and onion powder. Mix until well blended.

Spread the cheese mixture generously onto two slices of bread.

Top with the remaining slices of bread to create sandwiches.

Heat a skillet over medium heat and add 1 tablespoon of butter.

Once the butter is melted, place the sandwiches in the skillet. Cook until the bottom is golden brown, about 3-4 minutes.

Carefully flip the sandwiches and add the remaining tablespoon of butter to the pan. Cook until the other side is golden and the cheese is melted, about another 3-4 minutes.

Remove from the skillet, slice in half, and serve warm.