Preheat the oven to 180 °C.
Roll out the pastry on a floured board.
Cut out rounds of pastry and line greased 10 cm loose-bottomed tartlet pans with them.
Cut out slightly bigger circles of greaseproof paper.
Line the pastry with paper circles and fill with beans.
Bake blind for five to 10 minutes.
Place potatoes, carrots, parsnips, onion, garlic, sage and oil in a roasting dish and toss.
Roast for 35 to 40 minutes or until garlic has softened and the vegetables are tender.
Take the dish out of the oven and add the verjuice, chicken stock and Worcestershire sauce.
Mix in the flour, and stir over a low heat until it boils and thickens. Add the peas.
Remove from the heat and set aside to cool.
Then spoon the mixture into the baked pastry cases.
Cut the leftover pastry into strips.
For each pie, weave six pieces of pastry together to make a lattice on top.
Press to seal the edges and brush with egg to glaze.
Bake for 20 minutes or until the pastry is crisp and golden.
Eat these cold, especially outdoors on a picnic, or cover them with gravy and eat them hot with mash.