Preheat oven to 200'C, gas mark 6. Melt butter in oil in a large wide-based pan, and gently fry the onions for 10 minutes to soften. Add the pecans and garlic, cook for 1 minute, then stir in the kale and 1 tbsp water (you may need to do this in batches). Season, cover and simmer gently for 8-10 minutes until tender. Uncover and cook for 2 minutes, then drain in a colander. Allow to cool.
Put the cooled kale mixture in a large bowl and fold in the nutmeg, feta, eggs and dill.
Brush an ovenproof dish (about 20 x 30cm, 8x12 in) with oil. Use 4 filo sheets to line the dish, brushing with oil and overlapping as you go. Put in the filling and spread it evenly over the dish. Fold over the excess pastry.
Oil the remaining filo and use it to top the pie, oiled side up. Use a sharp knife to score the top into 6 equal pieces. Scatter with caraway seeds and bake for 30-35 minutes until golden and crisp. Serve warm or at room temperature.