1. Begin by making the filling. Heat the olive oil in a large frying pan and add the shallots. Fry until softened, about 5 mins. Add the leek and garlic and cook for a further 3 mins, then tip into a large bowl to cool.
2. In the same pan, fry the bacon lardons until browned and starting to crisp up, approx 5 mins. Blanch the peas in boiling water for a couple of minutes, then drain. Add the peas to the bowl with the shallots and leek and mix together. Allow to cool completely.
3. Meanwhile, preheat the oven to 190°C/gas mark 5. Roll out 2/3 of the pastry and use to line a loose-bottomed 20cm/8in cake tin, all the way to the top. Roll out the remaining pastry slightly thinner than before and use a plate about 20cm in diameter as a guide to cut out a circle for the lid. Refrigerate until needed.
4. Beat 3 of the eggs into the pea and leek mixture and season with salt and pepper. Add the cheddar cheese.
5. Scatter the lardons over the base of the pastry case then crack in 6 eggs. Pour over the egg, pea and cheese mixture then fold the sides of the pastry down over the edge of the filling. Brush the rim of the case with the remaining beaten egg. Top with the pastry lid, pressing to seal. Use any leftover pastry to decorate the pie if desired. Finally, brush with more beaten egg and bake in the oven for 50 mins- 1 hour until golden brown and cooked through.