Gather all ingredients. Preheat an outdoor grill for medium heat and lightly oil the grate.

Mix cream cheese, Cheddar, Parmesan, and garlic powder together in a bowl until the mixture is thoroughly blended.

Lay jalapeño pepper on a work surface and cut a lengthwise sliver from the side of the pepper, exposing seeds and white membrane. With the handle of a teaspoon, scrape out seeds and membrane, leaving the hollow pepper. Repeat for the rest of the peppers.

Chop up pepper slivers and mix into cheese stuffing. Stuff each pepper with cheese mixture and wrap each stuffed pepper in a half bacon slice. Secure with toothpicks.

Grill stuffed jalapeños on a less-hot part of the grill, turning as needed, until peppers are tender and juicy and bacon is browned and crisp, 30 to 40 minutes.