Preheat oven to 400 degrees and line a baking sheet with parchment paper.
Combine potatoes, bell pepper, onion, garlic, serrano pepper, paprika, cayenne, pepper, butter and olive oil in a large bowl. Stir to coat evenly.
Spread potato mixture on the baking sheet. Place in the oven for 25 minutes, flipping halfway. Increase heat to 500 degrees and cook until crispy - approx. 10 minutes.
Remove from oven and top with salt and cilantro.
Serve with hot sauce or ketchup.
Enjoy!