Heat the oil in a large heavy-bottomed pot over medium heat until shimmering and fragrant. Add the diced onion and cook, stirring occasionally, until translucent and soft, about 5 minutes.
Add the minced garlic and grated ginger to the pot, cooking for about 1 minute until fragrant and slightly golden, stirring constantly to avoid burning.
Toss in the cumin and turmeric, stirring constantly for about 30 seconds until the spices are toasted and fragrant. This enhances their flavor and aroma.
Add the diced potatoes to the pot, stirring well to coat them with the spice mixture. Cook for about 5 minutes, stirring occasionally, until the potatoes start to soften and turn slightly golden around the edges.
Pour in the vegetable broth, stirring to combine. Bring the mixture to a gentle simmer, then reduce the heat to low, cover partially, and cook for 15 minutes until the potatoes are tender when pierced with a fork.
Uncover the pot and stir in the defrosted and drained peas. Cook uncovered for another 5 minutes, allowing the flavors to meld and the sauce to slightly thicken. The peas should be bright green and tender.
Stir in the coconut milk, then season with salt to taste. Let the curry simmer gently for a few minutes to warm through and develop a creamy consistency.
Remove the pot from heat, squeeze fresh lemon juice over the curry, and stir gently. Taste and adjust salt or acidity as needed.
Garnish with chopped cilantro for a fresh burst of flavor. Serve hot over rice or with flatbread for a cozy, satisfying meal.
