How to Make It
Combine peaches, water, sugar, ginger, and mustard in a large saucepan. Bring to a boil over high. Reduce heat to medium, and cook, whisking often, until mixture is thickened and peaches have broken down, 12 to 15 minutes. Remove from heat.
Place peach mixture in a blender. Remove center piece from blender lid; secure lid on blender, and place a clean towel over opening in lid. Process until smooth. Stir in ketchup, salt, and pepper.