1) Slice off root tip and stem tip of three large beets and roast them in a 400 degree oven until they are tender, about an hour.
2) Slice the top off of half a head of garlic, exposing the cloves. Wrap in foil, drizzle with a bit of olive oil and a pinch of salt. Roast for 30 minutes at 400 degrees.
3) Once beets are roasted, let them cool and then peel and cube them.
4) In a large pot, add a few tablespoons of olive oil and the sliced leek. Let cook until soft over medium heat, just a few minutes.
5) Add cubed beets and roasted garlic along with thyme and bay leaf. Add stock and bring to a simmer. Cover and simmer for 5-10 minutes.
6) Discard bay leaf and blend with a blender.
7) Add lemon juice and season with salt and pepper. Serve with lots of crusty bread.