Heat oven to 400 degrees. Well before that, set bacon out to thaw to room temperature so it is pliable.
In mixing bowl, use rubber spatula to combine mashed potatoes and garlic herb cheese. Stir until incorporated. Spread 1 teaspoon mashed potato mixture in each jalapeno half; level each with butter knife or spatula.
Wrap each jalapeno with bacon; use three half-slices for large jalapenos or two halves for smaller sizes. Be sure bacon is wrapped sealing in mashed potato mixture tightly.
In small mixing bowl, combine brown sugar and cayenne pepper. Generously sprinkle over bacon and pat gently to make it stick.
Line cookie sheet with piece of parchment paper so sugar does not burn to pan. Bake until bacon reaches desired crispiness, around 25-35 minutes. Let peppers cool slightly before serving, about 5 minutes.