Boil potatoes in salted water for about 20 minutes. Drain well and mash. Set aside.
Preheat oven to 400°F.
Line your baking sheet with parchment paper.
In a medium skillet, heat oil over medium-high heat. Cook onions, coriander seed, curry powder, ginger, salt, turmeric, cumin, allspice, cayenne pepper, and cinnamon for about 5 minutes until onions are lightly browned.
Remove from heat and add peas, tomatoes, and mashed potatoes. Combine thoroughly and let it cool completely. You can already keep this mixture in an airtight container and refrigerate until ready to use.
When ready to cook, cut the prepared pie crust into triangles. Spoon the filling inside the triangle. Fold into a triangular hat shape and seal. Brush the samosas with egg whites.
Arrange on the prepared baking sheet and bake fore 15 minutes until golden brown.