Slice one jalapeño into thin rounds for garnish; set aside. Seed and finely dice remaining jalapenos.
In large bowl, combine mascarpone, cream cheese, cheddar, garlic powder and diced jalapenos. Spread mixture on bottom of 1-quart baking dish.
In separate bowl, combine Parmesan, panko breadcrumbs and melted butter; mix to combine. Sprinkle breadcrumbs evenly over the dip. Top with reserved jalapeno slices.
Bake 30 minutes, or until dip is bubbly. Allow to cool at least 5 minutes before serving. Serve with tortilla chips or crackers.
Notes
Jalapenos are not as spicy once the inner ribs and seeds are removed. To retain some heat, leave the seeds in 2-3 jalapenos you are dicing.