Lamb and Feta Frittata

Name: Lamb and Feta Frittata
Ingredients: 1 garlic clove, finely grated; 1 tablespoon za’atar; 3 tablespoons olive oil, divided; ½ teaspoon finely grated lemon zest, plus more for serving; 1 teaspoon fresh lemon juice; 4 ounces ground lamb; Kosher salt; 8 large eggs; ¼ cup plain whole-milk yogurt, plus more for serving; Freshly ground black pepper; 2 scallions, thinly sliced; 2 cups baby kale, tough stems removed; ½ cup cilantro leaves with tender stems; ¼ cup crumbled feta; ¼ cup torn basil leaves; 1 tablespoon tarragon leaves; Mild red pepper flakes and more torn herbs (for serving)