Place the olive oil in a large pan with the onion on medium heat and saute until soft and translucent. Stir constantly to avoid sticking or burning.
Add the finely chopped ginger, the crushed garlic and curry paste to suit your taste stiring until it becomes fragrant.
Drain and rinse the lentils and place in the saucepan, add the stock to cover the lentils by about a finger width. Bring to the boil add the sweet potato bring to the boil again then turn the heat down to low and cover to simmer slowly.
Test the lentils after 20-25 minutes to see that they cooked through, if so add the baby spinach and the coriander stiring through until wilted.
Once the spinach is soft, season with salt and pepper to taste. Serve topped with sprigs of coriander.