Preparation:

• For the dough, knead all the pasta dough ingredients in a stand mixer using the dough attachment for 20 minutes or until smooth and elastic.
• Shape the dough into a long, flat rectangle. Cover with a clean damp cloth and leave to rest in the fridge for 2 hours.
• For the cheese filling, cut the cheese into small cubes and blend with the cream in a Thermomix at 70°C for 8 minutes. Add the potato starch dissolved in water and blend for 1 minute more. Alternatively, carefully melt the cheese and cream in a sauceapan, stirring continuously (don't let it boil) then stir in the potato flour. Pour into a bowl and allow to cool quickly.
• Roll out the dough using a pasta machine, working down through the settings until it is on its thinnest setting, dusting with flour to prevent sticking. Cut the dough in half.
• Using a piping bag, pipe teaspoons of the filling in lines on one piece of the pasta dough at 2cm intervals, leaving a 1cm border along each edge.
• Place the other piece of dough on top, pressing the two pieces of dough together, pressing down gently to exclude any air. 
• Use a serrated pastry wheel tocut out the classic raviolo shapes.
• Cook the ravioli in a large pan of boiling salted water for 4 minutes then carefully drain.
• While they are cooking, heat the chicken stock and divide among serving bowls. Add the ravioli, drizzle over some melted chicken fat, sprinkle over the barberries and serve immediately.