Sieve the flour in a bowl then add the salt, sugar, vinegar and finally the water, a little at a time. Knead until the dough comes together and does not stick to your hands. Gather to a ball, cover and let it rest for 30 minutes. Divide it into 2 equal parts. Roll each out to a 2-3mm thick rectangle. Spread half the fat evenly over. Roll the pastry sheet over and then fold one third into the middle and then the other third on top. Chill them in the fridge for 1h. Prepare the cream filling. Place the milk, rice flour and salt in a saucepan and simmer for 8-10 minutes until the mixture thickens. Remove from heat. Add the crumbled cheeses and the whisked eggs and combine everything well. You can flavour with nutmeg or paprika. Season with plenty of freshly ground pepper. Leave to cool completely. Roll the first pastry half out to a very thin sheet. Lift it onto a shallow, greased baking pan and push it into the sides, letting any excess pastry hang over the edge. Empty the filling in. Then roll out the second half and cover the pie. Fold the edges of pastry hanging over the sides back over the pie. Place in the fridge for 1h. Whisk the egg and the olive oil together and brush the pie all over. Score in wedges. Bake in a preheated oven at 180ºC. At first, just bake the bottom of the pie for 40 minutes (heating only the bottom element), and then bake the whole pie for another 40 minutes (heating both elements).