Using plastic gloves (if possible), slice the jalapenos open lengthwise and scoop out the seeds. Set aside.
By hand or in a stand mixer with the paddle attachment, evenly combine the mascarpone, cheddar cheese, chives and 1 tablespoon of half and half.
Stuff the mixture into each jalapeno half.
Whisk together the egg, 2 tablespoons half and half, salt, paprika and garlic powder in a small bowl.
Place the flour and panko in separate bowls and line them up with the egg mixture to create a breading station.
Dip a jalapeno in the flour and tap it to remove the excess. Next, dip it in the egg mixture and then finish with the panko. Scoop extra panko on top and gently press it in place.
Place the jalapeno on the prepared baking sheet and repeat the process with the rest of the jalapenos.