Pre-heat the oven to 425 degrees. Line a large baking sheet with parchment paper or a silicone baking mat.
Place the cauliflower florets on the prepared baking sheet. Drizzle with 1½ tablespoons of the olive oil, season with salt and freshly ground black pepper, and toss to coat. Arrange the florets in an even layer, making sure to leave a little bit of space between each one. (Spacing is important! If you crowd the florets, they’ll steam instead of getting crispy and caramelized.) Roast for 20 to 25 minutes or until the cauliflower is tender and lightly browned.
Meanwhile, cook the farro according to the package directions. Drain and briefly set aside. (Now is the time to decide whether you want a warm salad or a room temperature salad. I personally like to let the cauliflower and farro cool to room temperature before combining, but you can definitely assemble the salad while warm if you prefer.)
In a medium mixing bowl, whisk the remaining 2½ tablespoons of olive oil, red wine vinegar, garlic, and honey until emulsified (aka well combined).
Add the farro to the bowl with the dressing and toss to coat. Next, add the cauliflower, parsley, sun-dried tomatoes, and almonds. Toss to combine, then gently fold in half of the feta. Taste and season with extra salt and pepper if needed. (If you like things tangy, you may also want to add more red wine vinegar.) Top with the remaining feta and serve.