Preheat the oven to 350ºF.
Trim the external fat from the lamb shanks.
Dice the onions, celery, and carrots. Crush the garlic cloves.
In a large, deep saute pan over medium-high heat, warm the olive oil until nearly smoking.
Season the lamb shanks with salt. Brown the shanks on all sides, about 5 minutes total. Transfer to a plate. Work in batches if you need to.
Add the onions, celery and carrots to the pan and cook, stirring occasionally, until the vegetables are golden and translucent.
Add the wine to deglaze the pan. Scrape up any browned bits of flavor from the bottom of the pan.
Bring the wine to a simmer, and add the stock, thyme, garlic, bay leaf and shanks and bring to a boil.
Cover the pan, transfer to the oven and cook for about 2 hours or until the meat is almost falling off the bone. Using tongs, transfer the shanks to a large serving bowl.
Remove the bay leaf.
Using a blender, puree until smooth.
Season the sauce with salt and pepper. Pour the sauce over the lamb shanks and serve!