In a medium skillet, heat tablespoon of the olive oil. Add the lamb and cook over moderately high heat until browned all over, 6 to 7 minutes. Using a slotted spoon, transfer the lamb to a plate. Add the onion to the skillet along with the remaining 1/2 tablespoon of oil and cook over moderately low heat, stirring, until softened, 3 to 4 minutes.
Return the lamb to the skillet, add the potato and cook until sizzling. Add the curry powder, cumin, coriander and cayenne and cook over low heat, stirring constantly, just until slightly darkened, about 4 minutes. Add the broth and bring to a simmer, stirring, to scrape up any browned bits from the bottom. Cover the skillet and cook over low heat until the meat and potato are tender, about 30 minutes. Remove the lid and cook until the liquid is absorbed. Stir in the peas and season with salt. Transfer to a bowl and let cool completely.
Preheat the oven to 400°. On a lightly floured surface, roll out the pie crusts, 1 at a time, to a bare 1/8-inch thickness and cut out a total of 40 rounds with a 2-inch round biscuit cutter. Lightly brush the rounds with water, top with a scant teaspoon of the filling and fold in half. Sea] the edges a fork. Transfer the samosas to a large baking sheet .
Bake the samosas for 35 to 40 minutes, or until the crust is golden. Serve hot or at room temperature.