Step 1

Place the potatoes into a large pot of salted water and set it over high heat. Bring the water to a boil and cook the potatoes until fork tender, about 10 minutes.

Step 2

Drain the potatoes into a colander and return them to the pot.

Step 3

Melt the butter in a large skillet over medium heat. Add the onion and cook it until soft and translucent, about 5 minutes, stirring frequently.

Step 4

Add the garlic, ginger, serrano pepper, ground cumin, cumin seed, garam masala, and turmeric to the skillet. Toast the spices for about 1 minute, until very fragrant.

Step 5

Add the spinach and water to the skillet. Stir everything and cook until the spinach has fully wilted and most of the water has evaporated, stirring frequently, about 5 minutes.

Step 6

Add the coconut milk and potatoes to the skillet. Gently stir everything to distribute the potatoes while you bring the coconut milk to a simmer.

Step 7

Remove the skillet from heat and stir in the lemon juice. Season the curry with salt and pepper to taste.

Step 8

Divide onto plates and serve.