Preheat your oven to 400°F.
In a small bowl, whisk together the olive oil, minced garlic, salt and pepper.
Place the chopped bell peppers, eggplant and red onion in a large bowl and drizzle with the olive oil mixture. Toss to coat.
Spread the vegetables in a single layer on a 15x10x1-inch baking pan coated with cooking spray.
Roast until the vegetables are softened and lightly browned, 45 to 50 minutes, stirring once halfway through cooking.
Let the vegetables cool slightly, then transfer them to a food processor.
Add the tomato paste and pulse just until blended, stopping while the mixture still has some texture.
Spoon the eggplant spread into a serving bowl and let it cool completely before serving.
Set out toasted baguette slices, crackers or fresh vegetables for dipping.
