Crumble the yeast and mix with the milk and sugar.
Put the flour into a bowl and make a well in the centre.
Add the egg yolks, butter and yeast mixture and knead to a smooth, heavy dough.
Add a little more flour or milk if necessary (the dough should be neither sticky nor crumbly).
Shape into a ball, put into the bowl, cover with clingfilm and chill overnight.
For the filling
Heat the oil and gently cook the onion and garlic until soft.
Add the red pepper and jalapenos and cook for 5 minutes.
Add the meat and cook, breaking it up with a fork to brown right through. Season with salt and pepper.
Mix together the egg, creme fraiche, tomato purée and chopped parsley and stir into the meat mixture.
Add a few breadcrumbs if the mixture is too soft.
Season with salt and pepper and add chilli powder to taste.
Roll out the dough thinly on a floured surface and cut out 12-15 cm|4"-6" circles with a round cutter.
Put a little of the filling in the middle of each circle, fold the pastry over the filling and press the edges together firmly (decorate the edges with the prongs of a fork or roll the edges over to make a decorative twist).
Heat the oven to 200°C (180° fan) 400°F gas 6. Grease a baking tray.
Whisk the egg yolks with 1-2 tbsp water and brush over the dough.
Place on the baking tray and bake for 15-20 minutes, until golden brown.