1. Line a strainer with 2 layers of cheesecloth and place it over a bowl. Add the yogurt and close the cheesecloth with a twistie. Let drain for 3 hours at room temperature.
2. Place the drained yogurt in a bowl and stir in the walnuts, garlic, 2 tbs of the mint, the orange zest, honey, salt, and pepper.
3. Transfer the mixture to a serving bowl and sprinkle with the remaining tsp of chopped mint. Refrigerate covered for up to 3 hours before serving. Twenty minutes before serving, remove the yogurt slather from the refrigerator.