Slice each jalapeño in half lengthwise and remove the seeds and membranes. If you prefer less heat, rinse them under cold water after scooping.
In a small bowl, mix cream cheese, cheddar cheese, garlic powder, salt, and pepper until smooth. Spoon or pipe the mixture into each jalapeño half.
Dredge each filled jalapeño in flour, dip in beaten egg, and roll in breadcrumbs. For extra crunch, repeat the egg and breadcrumb step once more.
Heat oil in a deep pan to 175°C (350°F) and fry the poppers until golden brown, about 2–3 minutes per side. If baking, arrange them on a lined tray, brush lightly with oil, and bake at 200°C (400°F) for 15–18 minutes until crisp.
Let them cool slightly before serving with ranch, sour cream, or your favorite dipping sauce.