Potato Curry Sandwich

Name: Potato-Curry Sandwich
Ingredients: 4 medium Russet potatoes, peeled and chopped into 1-inch cubes; 1 tablespoon oil or ghee; 1/2 teaspoon whole cumin seeds; 1 pinch asafoetida powder; 1 pinch ground turmeric; 1 small jalapeño, seeded and finely chopped; 1 small red onion, finely chopped; 1/2 cup frozen peas; 1/2 teaspoon garam masala; 1 teaspoon kosher salt, plus more to taste; 1 handful fresh cilantro, finely chopped; 8 pieces white sandwich bread, one side lightly buttered; 1 handful shredded cheddar cheese, per sandwich (optional)