Brush the bell and poblano peppers with the olive oil. Char over a gas flame using tongs, then peel and discard the skin and remove the ribs and seeds.
Puree the peppers and ketchup in a blender until smooth.
Transfer the puree to a bowl. Stir in the mustard, horseradish, paprika, chili powder, black pepper, garlic powder and hot sauce until well combined.
Keep in an airtight container in the refrigerator for up to 2 weeks.
Recipe courtesy of Marcus Samuelsson