Preheat oven to 400 degrees. In a medium bowl, toss radishes with olive oil, thyme, oregano, black pepper, and salt.
Spread radishes on a baking sheet in a single layer and roast for 20 to 25 minutes, flipping halfway through, until tender and slightly golden.
In a food processor, combine feta, Greek yogurt, olive oil, lemon juice, dill, parsley, garlic powder, onion powder, thyme and oregano. Blend until smooth.
Spread whipped feta dip onto a serving plate or shallow bowl. Arrange warm roasted radishes over dip and drizzle with a bit of additional olive oil if desired. Optional: garnish with more dill, crumbled feta and chopped pistachios. Enjoy!