Using a food processor

Put the flour, salt, butter and lard into the food processor and whizz until the mixture looks like very fine breadcrumbs.

With the motor still running, add iced water, 1 tbsp at a time, until the mixture starts coming together.

Making by hand

Stir the flour and salt together in a bowl. Rub in the butter and lard so that the mixture resembles fine breadcrumbs.

Add 3 tbsp of cold water and stir it in with a round bladed knife. Continue adding tablespoons of water and stirring until the mixture starts coming together.

Turn out onto a lightly floured surface and gently knead into a smooth ball.

Flatten into a disc then wrap in foil or cling film and chill in the fridge for at least 30 minutes.

Put the oil and butter in a frying pan over medium heat.

When hot, add the onion, season with a little salt and pepper, and cook, stirring often, until it's softened and lightly browned (approx. 10 - 12 min.): add the garlic for the final few minutes.

Take off the heat and leave to cool.

Put the sausage meat, chopped chestnuts and breadcrumbs in a large bowl. Add the cooled onions and their juices plus the fennel seeds, sage, thyme, half a teaspoon of salt and a generous amount of black pepper. Stir everything together very well.

Taste a sample of the filling: break off a small piece and roll into a ball. Put a little more oil in the wiped-out frying pan, fry the ball until cooked through then leave to cool. Taste and adjust the pie filling if necessary, e.g. add more salt, pepper, or herbs.

On a lightly floured work surface, roll out the pastry thinly: approximately 2 mm.

Stamp out 12 circles large enough to come all the way up the sides when placed in the holes of a deep muffin/bun tin (approx. 10 - 11 cm diameter) plus 12 smaller circles for lids (approx. 7 - 8 cm diameter). You will need to gather the scraps and re-roll to make all 24 circles.

Place the 12 larger circles in the holes, gently pressing down so they sit on the bottom and come up the sides. Neaten the top edge by pressing down and smoothing with your fingers.

Divide the filling into 12 pieces (use scales for accuracy) and roll into a ball. Put one in each pastry case and press down to level it.

Brush some of the beaten egg all around the edge of each pastry case then put one of the smaller circles on top as a lid. Press down all around to seal: to make a pattern, use the end of a wooden spoon or the tines of a fork (dip in flour now and then to prevent sticking) and press all around the edge.

Tip: pies can be chilled at this point if convenient (chilling for a short while also means the pastry is less likely to shrink and the pattern you made around the edges is more likely to remain after baking).

Preheat your oven to 200°C /180°C Fan /Gas 6 /400° F with a shelf positioned in the middle.

Brush the pies generously with more of the beaten egg, then make a hole in the top of each one using the end of a wooden spoon.

Transfer to the preheated oven and bake for 40 minutes or until the pastry is golden and the filling piping hot: if you have a food thermometer, the filling needs to reach 65°C (150°F).

Tip: halfway through cooking, you may wish to add another layer of beaten egg and also turn the tin around for even baking.

When the pies are done, place the baking tray on a cooling rack for 5 - 10 minutes then carefully remove the pies and place them directly on the rack.

Leave until completely cold before eating or storing.

Keep in the fridge and use within 3 - 4 days or can be frozen (defrost thoroughly overnight in the fridge).

Best eaten if taken out of the fridge 20 - 30 minutes in advance.