Begin by boiling the peeled and diced potatoes in a saucepan of salted water for about 10 minutes, until they’re tender and easily pierced with a fork. Drain and set aside to cool slightly.
While the potatoes cook, toast the cumin seeds in a dry skillet over medium heat until fragrant, about 1 minute. Add a tablespoon of vegetable oil to the pan, then toss in the toasted seeds to release their aroma. Remove from heat and let cool.
In a mixing bowl, mash the cooked potatoes with a fork until smooth but still slightly chunky. Stir in the green peas, toasted cumin seeds, garam masala, coriander powder, cayenne (if using), lemon juice, and a pinch of salt. Mix well to combine all the spices evenly.
Unroll the puff pastry sheet on a clean surface and cut it into strips about 3 inches wide. Keep the remaining pastry covered with a damp towel to prevent drying out.
Spoon about 1 to 2 tablespoons of the filling onto one end of each pastry strip. Fold the pastry over the filling into a triangle shape, pressing gently to seal the edges. Use a little water or beaten egg along the edges if needed to ensure they stick well.
Arrange the filled samosas on the prepared baking sheet, leaving space between each. Brush the tops with the beaten egg for a shiny, golden finish.
Bake in the preheated oven at 200°C (392°F) for 20 to 25 minutes, until the samosas are deep golden brown and crispy around the edges. Rotate the tray halfway through to ensure even baking.
Once baked, transfer the samosas to a cooling rack and let them rest for about 5 minutes. This helps the crust set and makes them easier to handle.
Serve the baked samosas warm, accompanied by chutney or yogurt for dipping. Enjoy the crispy, flavorful bites that are lighter than their fried counterparts.
