1 In a blender container or food processor bowl, combine the lemon juice, oil, sugar, salt, and black pepper. Add the onion and about one-third of the cut-up sweet peppers.
2 Cover and blend or process until smooth. Add the remaining cut-up sweet peppers; cover and blend until smooth. Transfer mixture to a mixing bowl. Let stand, covered, at room temperature at least 2 hours.
3 Place pureed vegetable mixture in sieve, pressing gently to drain off excess liquid. In a medium mixing bowl combine cream cheese, mayonnaise, horseradish, and hot pepper sauce.
4 Stir in pureed vegetable mixture. Cover and refrigerate for 2 to 3 hours. Spoon into the whole sweet pepper shells. Place filled peppers in the center of a serving platter; surround with vegetable dippers and/or breadsticks. If desired, garnish with fresh herbs.