Preheat oven to 180°C. Fold two sheets of filo pastry widthways into four then cut in half. Brush sheets with melted butter and press firmly into the base and sides of a nonstick muffin tin. Beat the eggs and buttermilk together in a bowl, add spring onion and season to taste.
Divide pumpkin and spinach between each tart case. Pour in egg mixture and sprinkle each tart with cumin seeds. Top with grated cheese and bake in oven for approximately 15 mins or until set.