Mix the filling ingredients and season. Grease 12 holes of a muffin tin and line each with a strip of baking parchment, to make pies easier to remove from tins.
To make pastry, bring the lard and 250ml water to the boil in a small pan. Sieve the flour into a food processor and add 2 tsp salt. While processor is on, pour in lard and water mix, then blend until you have a smooth dough. Turn out into a bowl and remove two-thirds, covering the final third with a tea towel to keep warm.
Roll larger piece out on a floured surface to about 2-3mm thick – work quickly as the dough is easier to work with when warm. Cut out 12 x 11cm circles using a pastry cutter. Line each hole of the tin with the circles, pushing them in with your fingers and leaving a slight overhang.
Heat oven to 180C/160C fan/gas 4 and put in a baking tray. Divide filling between pastry cases, pushing down lightly. Roll out remaining pastry on a floured surface and stamp out 12 x 8cm circles. Brush edges of filled cases with egg, then put lids on top. Pinch together and crimp the edges with your fingers. Brush with beaten egg and set aside the rest for later.
Bake in oven for 30 mins, then remove the tin and tray, and gently take the pies out of the holes. Brush the sides and top again with egg and place directly onto the baking tray. Turn oven to 200C/180C fan/gas 6 and cook for 25-30 mins until the sides are set and tops a deep golden colour. Remove and cool on a wire rack.