Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
Slice the jalapenos in half lengthwise and remove the seeds and membranes to reduce the heat, if desired. Place the jalapeno halves cut-side down on the baking sheet.
Roast the jalapenos in the oven for about 10 minutes, or until they are slightly charred and softened. Remove from the oven and let cool for a few minutes. Chop the roasted jalapenos into small pieces.
In a small bowl, mix the softened cream cheese and chopped jalapenos until well combined.
Heat the frying pan or skillet over medium heat. While it heats, spread butter on one side of each slice of bread.
On the non-buttered side of two bread slices, spread half of the cream cheese mixture. Top with half of the shredded cheddar cheese.
Place the other two slices of bread on top, buttered side up. Carefully place the sandwiches in the heated frying pan.
Cook for approximately 3-4 minutes on one side, or until the bread is golden brown and the cheese begins to melt. Flip the sandwiches using a spatula and cook for another 3-4 minutes on the other side.
Once both sides are golden and the cheese is melted, remove the sandwiches from the pan. Let them cool for a minute before slicing in half.