Thai Curry Lentil & Sweet Potato Soup


1 tbsp olive oil
1 medium onion, diced
2 cloves garlic, sliced
1 tbsp ginger, peeled & diced into small pieces
1 tbsp Thai red curry paste {I like this brand}
1 medium sweet potato {500g}, peeled and diced into ½ inch cubes.
3 cups stock {veggie or chicken}
¾ cup dried red lentils
1 tbsp fish sauce
1 tbsp lime juice

After simmering:

1 can light coconut milk {400mL}
¼ tsp salt {or more; to taste}
1 tsp lime juice
1 tsp fish sauce