Heat vegetable oil in a large pot over medium heat. Add chopped onion and garlic, cooking for 4–5 minutes until soft and translucent.

Stir in cumin and oregano, cooking for about 1 minute until fragrant. Lower the heat if the spices begin to stick.

Add diced potatoes and broth. Bring to a gentle boil, then reduce heat, cover, and simmer for 15–20 minutes until the potatoes are fork-tender.

Blend half of the soup using a blender or immersion blender, then return it to the pot. Let the soup cool slightly before blending to prevent splattering.

Stir in evaporated milk, season with salt and pepper, and simmer gently for 5 more minutes until smooth and slightly thickened.

Ladle into bowls and garnish with fresh cilantro before serving.