Preheat the oven to 375°F and lightly grease a loaf pan.
In a large bowl, combine the ground beef, half the shredded cheddar, diced jalapeños, chopped onion, egg, breadcrumbs, milk, salt, black pepper, and garlic powder.
Mix everything with your hands or a spoon until the ingredients are evenly distributed.
Transfer the mixture to the prepared loaf pan and press it down evenly.
Sprinkle the remaining cheddar cheese over the top.
Bake for 50 to 55 minutes until the internal temperature reaches 160°F and the cheese on top is melted and golden.
Let the meatloaf rest for 10 minutes before slicing.