In a pan a low heat, add a little oil and the onion, cook for about 5 minutes. Add the tomato, chorizo and chicken. Let this cook for about 10 minutes. The sauce should have thickened. Taste and season and mix in some basil.
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.