01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - Arrange eggplant, red bell pepper, cherry tomatoes, and red onion on the prepared baking sheet. Drizzle with 1 tablespoon of the olive oil and season with a pinch of salt. Toss to coat evenly. Roast for 25–30 minutes, stirring halfway through, until vegetables are tender and golden.
03 - While vegetables roast, rinse farro under cold water. Combine farro with water or vegetable broth in a medium saucepan. Bring to a boil, then reduce heat and simmer uncovered for 20–25 minutes until farro is tender but still has a chewy bite. Drain any excess liquid.
04 - In a small bowl, whisk together the remaining 2 tablespoons of olive oil, lemon juice, dried oregano, minced garlic, sea salt, and black pepper until well combined.
05 - In a large mixing bowl, combine the cooked farro, roasted vegetables, and baby spinach. Pour the dressing over the mixture and toss until everything is evenly coated.
06 - Gently fold in the crumbled feta cheese, chopped parsley, and fresh mint if using. Divide among serving bowls and serve warm or at room temperature.