In a small bowl, thoroughly mix the softened cream cheese, diced jalapeños, and garlic powder until a uniform spread is formed.
Apply the room temperature butter evenly to one side of each slice of sourdough bread.
Place two slices of bread, buttered-side down, onto a cold non-stick skillet or griddle.
Spread the cream cheese and jalapeño mixture onto the unbuttered side of the bread in the skillet.
Distribute the crumbled bacon and shredded cheddar cheese evenly over the cream cheese layer.
Top with the remaining two bread slices, buttered-side facing up.
Adjust heat to medium-low and cook for 4 minutes, or until the bottom slice is golden brown.
Carefully flip the sandwiches using a wide spatula and cook for an additional 3 to 4 minutes until the cheddar is fully melted and the bread is toasted.
Remove from heat and allow to rest for 1 minute before serving to ensure the cheese sets.