Preheat oven to 200°C or 180°C fan. Line a baking tray with baking paper.
Place egg in bowl with salt and beat lightly. Add melted butter and milk and stir in flour with a fork to form a dough. Turn onto a floured surface and knead lightly.
Roll dough out thinly to a 28 x 38cm oblong. Spread over spinach, leaving a 25mm border. Top spinach with savoury mince.
Starting from long edge, roll dough up loosely, enclosing filling. Moisten ends with water and pinch together to seal. Use a sharp knife to cut roll into 2cm slices. Arrange on prepared tray and bake for 20-25 minutes, until golden brown.