Step 1

Melt 1½ teaspoons butter in 10-inch nonstick skillet over medium heat. Add garlic and cumin and cook, stirring constantly, until fragrant, about 30 seconds. Add kale and 1 pinch salt and cook, stirring occasionally, until wilted, about 2 minutes. Add tomatoes and cook, stirring frequently, until tomatoes are warmed through and no liquid remains in skillet, 1 to 2 minutes. Remove skillet from heat. Push kale mixture to side of skillet opposite handle and top with feta. Set aside.

Step 2

Beat eggs and remaining pinch salt in bowl until few streaks of white remain. Melt remaining 1½ teaspoons butter in 8-inch nonstick skillet over medium heat, swirling skillet to distribute butter across skillet bottom. When butter sizzles evenly across skillet bottom, add eggs. Cook, stirring constantly with rubber spatula and breaking up large curds, until eggs are mass of small to medium curds surrounded by small amount of liquid egg. Immediately remove skillet from heat.

Step 3

Working quickly, scrape eggs from sides of skillet, then smooth into even layer. Slide filling into center of eggs in 2-inch-wide strip perpendicular to handle. Cover for 1 minute. Remove lid and run spatula underneath perimeter of eggs to loosen omelet. Gently ease spatula under eggs and slide omelet toward edge of skillet opposite handle until edge of omelet is even with lip of skillet. Using spatula, fold egg on handle side of skillet over filling. With your nondominant hand, grasp handle with underhand grip and hold skillet at 45-degree angle over top half of plate. Slowly tilt skillet toward yourself while using spatula to gently roll omelet onto plate. Serve.