If the blanched kale is wet, squeeze or press it to remove excess liquid, then roughly chop so it fits in the blender.

Add to a blender: 2 cups packed blanched kale, ⅓ cup chopped scallions, ¼ cup packed parsley, 1 tablespoon packed tarragon, juice from one lemon, ¼ cup olive oil, ¼ cup-ish of water, and ½ teaspoon salt. Puree until mostly smooth. Transfer the puree to a bowl and reserve about 2 tablespoons for the omelette; keep the remainder for serving.

In a small bowl, whisk together 2 large eggs, 1 tablespoon heavy cream, and a pinch of salt until combined.

Heat an 8" skillet over medium-low. Add 2 teaspoons ghee and let it melt, tilting the pan to coat the surface.

Pour the egg mixture into the skillet. As the edges begin to set, use a spatula to lift the edges and tilt the pan so uncooked egg flows underneath. Continue until the top is mostly set but still slightly moist.

Spoon the reserved ~2 tablespoons of herb sauce onto the omelette and gently swirl/spread it into the uncooked areas. Continue cooking until the omelette is mostly set.

Sprinkle 2 tablespoons grated manchego over one half of the omelette. Fold the other half over the cheese, turn off the heat, and let the omelette rest in the pan for 1–2 minutes to finish cooking and melt the cheese.

Slide the omelette onto a plate and serve with the remaining herb sauce on the side.