Preheat broiler and set oven rack about 6 in from top of oven.
In 8 in cast iron skillet or oven-safe frying pan, warm 1 Tbsp grapeseed oil over medium-high heat. Add leek and green onions and cook, stirring often, until softened and lightly browned, about 4 minutes. Add parsley, dill, cilantro, and mixed greens, and continue cooking, stirring constantly, until wilted, about 2 minutes. Tip herb mixture into fine-mesh colander placed in kitchen sink and let any leached moisture drain away. With spoon, press mixture down to ensure herb mixture is not too wet. Set aside. Wipe out skillet and set aside.
In large bowl, whisk together eggs, turmeric, salt, and pepper until well combined. Stir in drained herb mixture and pumpkin seeds.
Place skillet back over medium heat and warm remaining 1 Tbsp oil. Pour in egg mixture, cover with lid, and cook until sides of frittata start to pull away from skillet and have begun to brown, about 5 minutes. Remove lid and transfer to oven under the broiler until egg is set, about 2 to 3 minutes. While warm, carefully unmould onto serving platter. Cut into wedges and serve.
Enjoy!