1In a medium pot, saute the onion, garlic and ginger in a drizzle of oil for a few minutes, until the onion softens. Add the lentils, yam, curry paste, salt to taste and about 1 1/2 litres of water (that's 6 cups), or chicken or vegetable stock. Bring to a boil, then turn the heat down, cover and simmer for half an hour or so, until the yam chunks are very tender.
2Add as much half & half (or 2%, or evaporated milk, or even heavy cream) as you like, and use a hand-held immersion blender right in the pot to puree it. Taste and adjust seasonings if it needs it.
3 Serve right away, or keep it in the fridge (or the barbeque) for up to a week to reheat when you want it.