1. Preheat oven to 375°. Coat 2 (5-inch) ramekins with butter.
2. Heat the ghee in a large skillet over medium heat. Add the leek and sauté until tender, about 8 minutes. Add the kale and sauté until wilted, about 2 minutes more. Let cool.
3. In a small bowl, mix together the eggs and feta and season with salt and pepper. Add the kale mixture.
4. Divide the mixture between the ramekins. Bake until a knife inserted near the center comes out clean, 20 to 30 minutes. Serve warm or at room temperature.
Ghee is a type of clarified butter traditionally used in Indian cooking. Due to its high smoke point, it is great for high-temperature cooking and is a good alternative to vegetable oils. The process of making ghee is similar to that for clarified butter, but the butter is cooked for a longer time alongside the milk solids, which gives it that great nutty taste. Ghee is the butterfat that is left over after the water and milk solids are removed from the butter.
Ingredients: 1 pound (4 sticks) high-quality unsalted butter
1. Cut the butter into squares and place in a medium saucepan. Bring to a boil over medium heat, then reduce the heat to medium-low and simmer the butter. After about 8 minutes, when the foam subsides and the butter turns a golden color, start stirring as it continues to simmer. When the butter foams a second time, after another 8 minutes, turn off the heat.
2. Let the butter cool down for a couple of minutes. Line a sieve with cheesecloth and set it over a bowl. Strain the butter through the cheesecloth. Discard the milk solids that remain in the cheesecloth.
3. Store the ghee in an airtight container at room temperature for up to 3 months. (Removing the milk solids inhibits spoilage, so it is OK to store at room temperature.) If you store it in the refrigerator, you can keep it for up to 1 year.