Bring a large pot of salted water to a boil. Cook the macaroni according to the package directions; drain.
Meanwhile, melt 2 tablespoons of the butter in a medium saucepan over medium heat. Add the panko and cook, stirring constantly, until golden brown, about 4 minutes. Transfer to a bowl.
Combine the half-and-half, mustard, garlic powder and remaining 6 tablespoons butter in the saucepan and bring to a bare simmer over medium-high heat. Add the Cheddar and processed cheese and stir until smooth. Stir in the macaroni and jalapenos and season with salt. Transfer to a serving bowl and sprinkle with the panko and cilantro.