In a pan over low heat, add a little oil and the red onion, cook for about 5 minutes. Add the black pudding and the apple. Cook this for about 5 minutes or so. Everything will have softened and will have started to mix together. Mix in the chutney, taste and season. Let this mix cool.
Preheat the oven to 190ºC.
Roll out the pastry, brush with some egg wash. Spoon some of the filling down the centre of the pastry. Fold the pastry over the filling and use a fork to push them together. Use a small knife to score the top of the pastry. Sprinkle some poppy seeds on the top. Cut them into the size required.
Place these on a tray lined with parchment and bake for about 15-20 minutes. Allow to cool on a wire rack.