Preheat the oven to 400F. Lightly grease a baking sheet.
Whisk oil and the next 4 ingredients in a large bowl. Add the eggplant, eggplant, peppers, onion; toss to coat. Place in a baking sheet. Roast vegetables, turning occasionally, until very soft and tender, about 30 minutes. Remove from the oven and cool to room temperature.
Add the mixture into a food processor. Add lemon juice. Using the pulse on, puree until blended. The spread can be made very smooth or left a little chunky, depending upon your preference.
Mix in the chopped parsley. Taste and season with salt, pepper, and additional lemon juice, as needed. Transfer to a bowl, cover, and refrigerate for at least 2 and up to 12 hours.
Toast Pita Bread briefly before serving
Notes
To serve: sprinkle parsley and crushed red pepper flakes on top. Accompany with pita bread or pita crisp, crackers, or fresh vegetables.